The Doctor had a strange look in his eyes as he brought the TARDIS to a stop and looked up at the viewscreen. The others looked, too. they saw trees and a fountain that sparkled in strong sunshine. The sky above was a clear, summery blue. It might well have been Earth, but his companions took nothing for granted.

“Where are we?” Wyn asked, it falling to her to ask the obvious question this time. “And when?”

“We’re on Earth,” The Doctor confirmed. “Mexico City to be precise, or one of the greener and quieter bits of it, anyway. In the year 2017.”

“Really?” Stella looked impressed. “Wow. Somewhere we could buy postcards and souvenirs from. Makes a change.”

“You could buy postcards from Betal-Kalsic,” The Doctor replied. “There’s a thriving tourist industry on that planet.”

“In the city, maybe,” Wyn pointed out. “But you brought us to the middle of nowhere, to meet a bunch of troglodytes who think you’re the anthropomorphic personification of their moon.”

“Not that it wasn’t interesting,” Jamie added. “They were very nice people once you got to know them. Though I thought the way they all assumed we were your three wives was a bit much. The moon and his three asteroid wives.”

The Doctor put on his most innocent expression.

“Is that why you’ve come as a man today, Jamie?” he asked. “So nobody would think we’re married?”

“I got fed up of being called the matron-wife,” Wyn complained. “It’s not fair. Jamie is older than me.”

“Matron-wife is an honoured place in the court of the moon god of Betal-Kalsic,” The Doctor pointed out. “Anyway, it is a beautiful summer’s day and there is something I really want to show you all. I suppose I shall have to wait until you change into summer outfits…”

The prospect of the Earth sun shining on them for a while appealed to Wyn and Stella, and they went off to dress suitably. Jamie, did, too, but casual clothes for the male form took less time than the female and he was back in the console room before them. He noted that The Doctor seemed a little more excited than usual about this location. He was positively ‘bouncing’. That was the only word for it. Bouncing. Jamie thought he looked like somebody who was going on a hot date. Except that his only preparation for it had been to run a comb through his hair, take off his tie and unbutton the top two buttons of his shirt. Even so, Jamie thought, if he did have an assignation with a lady, she would probably be dazzled by the smile on his face and not at all concerned with his sartorial choices.

He bent down under the console and opened a small panel. He took something from it and looked at it with a wistful expression for a moment before carrying on with his preparations. The object was a leather thong on which a black pendant was hung. The Doctor fastened it around his own neck and touched the pendant thoughtfully as he looked at his reflection in the smoked glass of one of the console’s monitor screens.

“I didn’t think ethnic jewellery was your thing, Doctor,” Jamie said as he stepped closer. He looked at the pendant curiously. It was made of some sort of shiny stone, cut quite thin and polished until it shone. There was a decoration, painted with an enamel-like deep blue paint that was either a flower or a star, or possibly both. It was obviously something The Doctor treasured. His hand automatically touched it, as if protecting it from Jamie’s too close gaze, and it seemed to be connected to the ‘bouncy’ and excited mood he was in.

Wyn and Stella noticed his unusual choice of ornament but decided not to ask.

It was very warm outside. The Doctor had left both his long coat and his suit jacket in the TARDIS and within a very short time he uncuffed his sleeves and rolled them up. He looked happy as he cooled himself in the fine spray of the waterfall they had seen on the viewscreen and then walked on. The ‘bounce’ was still there.

“He’s not meeting a woman,” Wyn assured her lover. “He’s not the sort, and you know it. Besides, he would hardly want us around if he was.”

The Doctor still didn’t say why they were here, but he did tell them that this was Chapultepec Park in Mexico City. He informed them that the word Chapultepec came from the Nahuatl language and meant ‘on the Grasshopper Hill.’ He went on at some length about how it was the home of the Aztecs when they first came to this part of Mexico in the 13th century, and had been the Royal Demesne of the kings of Tenochtitlán - the island capital of the Aztecs that was now modern Mexico City. He remembered especially the poet king Nezahualcóyotl, who built a palace there in the 1400s, as well as magnificent aqueducts that brought fresh water to the people of Tenochtitlán. He pointed out a rather grand statue of the said king who appeared to be part soldier and part bookworm, wearing Aztec battle dress and holding parchments in one hand.

A warrior poet? Well, why not.

“How does he get his tongue around those names?” Stella asked as his monologue continued. They were listening, and taking in what he was telling them as best as they could, but when he got onto the subject of the Aztec pantheon, and rattled off names like Xochipilli, Xochiquietxal, Cinteotl, Cihuacoatl and Huitzilopochtli, they started to lose the thread of it all. “Tenochti… Quex… Xovercoat or whatever he just said…”

“His own real name takes special breathing lessons to actually pronounce in one go,” Wyn pointed out. “I suppose these are easy.”

“He’s been here before,” Jamie said. “Look at the way he’s walking. He knows exactly where he’s going.”

“You’re right,” Wyn agreed. “Knowing him, though, I expect he was here in the reign of king Nezahoolacoatbuttons the poet king and helped him with the rhymes.”

All three laughed at the joke, but when The Doctor turned and looked at them he wasn’t laughing. He wasn’t even smiling. He seemed more than a little bit annoyed.

“Before we come into the company of people who would be highly offended by your comments, let’s get something perfectly clear and established. There has never been an Aztec god, goddess, emperor or high priest called overcoatle, coatlbuttons or Wylie Coyotly. What they did have was a fine, highly sophisticated, sometimes brutal, by your standards, but equally often, beautiful, culture, which I expect you all to respect from hereon or you can stay behind in the TARDIS with K9.”

They had been chastised, and deservedly so, they all realised. They murmured apologies to The Doctor and promised to behave. He nodded in acknowledgement of that and turned. He walked on ahead of them, but he didn’t tell them anything more about Nezahualcóyotl or anyone else and the mood of the day was spoiled. Wyn clutched Jamie’s hand. Usually that made her feel better, but both of them knew they had upset The Doctor and their enjoyment of each other’s company was marred by that, as was their appreciation of what was a thoroughly beautiful place all around them.

Stella looked at her sister and Jamie and then ran to catch up with The Doctor. She reached and took his hand. He looked at her as if she was surprised by that and then smiled at her. They walked like that for a few minutes and his smile broadened again. He put his arms around her shoulder and they waited for the other two to catch up. They were forgiven.

“Doctor,” Stella ventured. “Tell us a bit more about King… Nezahualcóyotl…” She got the pronunciation right. He positively grinned.

“Yes, I was here in the reign of King Nezahualcóyotl,” he admitted. “And no, I didn’t help him write the poems. But I was honoured with a private recitation of some of the king’s finest verses.” He recited a few lines in the original Aztec and was puzzled when he realised that nobody understood the words.

“Funny,” he said. “But Aztec used to be one of the languages that the TARDIS translated. I need to look at that. Never mind, there’s a seventeenth century Spanish translation....

Y tú, querido amigo,

goza la amenidad de aquestas flores;

alégrate conmigo,

desechemos las penas, los temores:

que el gusto trae medida

por ser al fin con fin la mala vida.

They all listened as he recited several stanzas of what was obviously a much longer poem. This time, they understood it. The TARDIS could manage even 17th century Spanish. It was a wonderful piece all about how important it was to celebrate the beauty of the world, to smell flowers, to dance and listen to music, because Human life is so short and it was important to embrace every experience fully.

“Are you sure you didn’t help him out?” Wyn asked. “Because that’s what you always tell us to do. Live life to the fullest potential. Make it fantastic.”

“No,” he answered. “If anything, I think he taught me that lesson. Because my life isn’t short, I suppose there was always a danger of me taking things for granted. The small, beautiful things of life. He taught me to stop and smell a flower, admire its delicate, perfect beauty, to appreciate such things fully. That’s why I parked the TARDIS so far from the museum. So that we could all do as Nezahualcóyotl said - enjoy the amenity of aquestas flowers – and the sun in our faces and the peace and friendship between us.”

They were all so pleased that The Doctor had forgiven them that they found it easy to do as he said. The half mile ramble through Chapultepec Park was enjoyable to them all before they reached the object of their journey, The Museo Nacional de Antropología.

They all recognised the flat, featureless, concrete architecture as typical of the 1960s. It seemed unimpressive except in the size of the sprawling building. Inside the main entrance, though, they found something guaranteed to impress. The central feature of the foyer was called ‘El Paraguas’ – The Umbrella. It was a tall, slender column with pre-Columbian designs on it, supporting, all by itself, the wide square roof. Around the column a fine curtain of water fell into a round trough below, but Jamie looked up at the illuminated, fan-like pattern around the top of the column and was reminded of something familiar.

“It’s the TARDIS console,” he said.

“It’s the foyer of the National Assembly in Cardiff,” Stella argued.

“It’s both,” Wyn agreed. “But it’s got to be coincidence, hasn’t it, Doctor?”

“Yes,” he answered. “The last time I was here was in my Eighth incarnation when the TARDIS looked a lot different. Anyway, come on, there’s lots to see…”

They took their time going around the huge exhibition of artefacts from Aztec, Mayan and Toltec civilisations. The Doctor, giving them an exclusive and extremely informative guided tour, got his tongue around even more exotic pronunciations. He had a small crowd listening to him as he described in detail how the Stone of the Sun, an elaborately carved rounded stone that was one of the treasures of the museum, actually worked as a perpetual calendar. And all the time he looked as if he was bursting with anticipation of something else. The bounce was back, along with a look in his eyes when he thought nobody was looking at him. He seemed to be deliberately holding back his full enthusiasm for something that was yet to come.

That enthusiasm found its outlet at last as they reached one of the special exhibit rooms. “La Dama Aztec” – the Aztec Lady. The brochure said it was one of the most exciting finds of recent years by the Museum’s own archaeological team working in southern Mexico. The centrepiece of the exhibit was the perfectly mummified remains of an Aztec lady of the fifteenth century AD. She had been found in an untouched tomb, perfectly preserved by the dry, moisture free air inside, along with a collection of fine grave goods that added to the understanding of the ordinary domestic life of an Aztec noblewoman. They included gold ornaments for the hair and body, pottery and obsidian, examples of needlework and beadwork that were still in wonderful condition, and even a sealed jar that proved to contain some very dried up fifteenth century cocoa beans. For some reason, that last made The Doctor laugh to himself, but he never explained the joke to his companions.

“Was she a princess?” Stella asked as they looked at the carefully preserved body inside a hermetically sealed glass case. It was a bit of a shock to them, seeing it like that. Her body had mummified naturally, instead of rotting to a skeleton. The flesh was like reddish-brown leather, tightly drawn around the bones, making her a little smaller than she was when she was alive. A diagram showed how much shrinkage must have taken place. She was dressed in a gown that was gold coloured originally, but now most of the colour had faded to a sort of creamy white linen colour. An interactive panel showed how the gown might have looked when it was put on her by those who attended to her body.

Jamie wasn’t looking at her dress. He was looking at the ornament around her neck. She was wearing a necklace of brightly coloured beads and the centrepiece of them was, according to the information panel, made of polished obsidian. The deep blue enamel, starlike flower painted on it was Turbina corymbosa, one of the five flowers of Macuilxochitl, the Aztec god of love, games, beauty, dance, flowers, maize and song.

It was the same design as The Doctor’s pendant.

“Doctor?” Stella repeated herself as he didn’t seem to be listening. “Do you know about her? Was she a princess?”

“No,” he answered, seeming to come back to the present from some place where he was smiling happily. “No, she was a gardener.”

“A gardener?” Stella was surprised. “But she’s like… buried in a special tomb, as if she was somebody important.”

“In a society with kings like The Doctor’s poetic friend,” Wyn said. “Maybe a gardener IS somebody important. Somebody who makes beautiful things grow…”

“Quite right,” The Doctor confirmed. He stepped right up to the glass case, ignoring the rope perimeter and the ‘do not touch the glass’ notice. He put his hands on the glass, over where the lady’s heart would be. His companions watched in amazement as he smiled softly and spoke, very obviously, to the mummified lady.

“Hello, my dear. It’s been such a long time. But you have always and ever been in my hearts, my dearest lady.”

“Oh… my… Lord…” Wyn exclaimed in a hoarse whisper as she clung both to Jamie’s hand and to Stella’s.

“Oh, no,” Stella said. “Oh, she can’t be. That’s too sad for words.”

Jamie said nothing. He’d worked it out already. He’d read what it said about cocoa in the information panel.

“Sir!” As The Doctor gazed lovingly at the long dead lady, clearly not seeing in his own mind’s eye the mummified face, but something else entirely, a woman called out to him. She was dressed in a smart skirt suit with a name tag identifying her as a staff member. She asked him politely but firmly to move back from the exhibit.

He looked around, slightly dazed at first, as if he had been dragged back reluctantly to the present moment. Then he smiled and apologised and did as she asked. The woman, whose name was Thalia Torres, according to her tag, looked at him and seemed surprised. She seemed about to say something else, but her attention was called to a group of tourists who were asking about the exhibit.

“There is a rather nice coffee shop not far away,” The Doctor said to his companions. “I think we deserve a refreshment break.”

And with that he turned and walked away. They followed him. But they were not going to let him off the hook so easily. They waited long enough for the waitress to bring their drinks and sandwiches, and then Wyn asked the question they all wanted to ask.

“Was she… really… Doctor… was she your… girlfriend? The Aztec lady?”

The Doctor smiled and took a sip from his cup. He hadn’t ordered coffee, but a cup of cocoa, prepared fresh from the roasted beans, in boiling water without milk or sugar. It made a bitter drink, but very satisfying and refreshing, and apparently reminding him of something that brought a glint to his eyes.

“Yes, sort of,” he admitted. “More than that, really. For a while… for a very brief, but rather wonderful time, we were engaged.”

“Engaged?” The word echoed three times around the group.

“Accidentally,” he admitted. “You know how I am always warning you lot about local customs, about not accepting food or drink if it’s prepared in any sort of ceremonial way, that sort of thing…” They all did. Stella especially had those sort of warnings from him all the time. Several times that advice had meant she avoided being married to the tribal chief or inducted as a vestal virgin.

“Well,” The Doctor grinned sheepishly. “I forgot my own rule, and found out too late that making cocoa and giving it to a lady while the two of us were alone, actually constituted a bond of betrothal. One I would happily have gone along with, I might add. She was the sweetest soul I ever met. But I had to get my companions away from the village because they’d got into quite a bit of trouble. My dear, sweet Cameca understood my dilemma. She herself broke off the engagement, freeing me from my obligation to her. But for a brief time... oh, if I had only myself to think of, spending my own declining years and hers, together in the Garden of Peace would have been an easy choice to make.”

“Oh, Doctor!” Stella was the one with a romantic heart. She reached out and touched his hand. “Oh, that is so sweet. What did you say her name was?”

“Cameca. A noble lady, a gardener and herbalist. The Aztecs knew how to do things with other plants than just cocoa, of course. Some of them would get a visit from the drug squad, these days, mind you. Even this innocent flower that she gave me as a love token has seeds that can be used as an hallucinogen. But Cameca mostly grew flowers for their beauty, for the joy of them in the way Nezahualcóyotl wanted them to be enjoyed. And for that she was honoured in her village.”

“Isn’t it… weird, though… a bit creepy…” Wyn approached her question carefully. “Seeing her like that… a 600 year old corpse… on display in a glass case for every twerp who comes through the door to stare at? Doesn’t that feel…”

“Yes, it does,” The Doctor answered her quickly. “What they call anthropology, yes, it’s very close to grave robbing, defilement. And I do wish they hadn’t. But the tomb was damaged by an earthquake in the area, and it was no longer sealed. And their grave robbing is for a better motive than others might have had. Besides… when I look at her… I don’t see what the tourists see. I can remember her face as it was.”

“Yes, I rather thought you could,” Jamie told him. “But was she…” Jamie saw The Doctor give a warning shake of his head and he stopped talking. The woman from the exhibition, Miss Torres, approached. She seemed to be looking for The Doctor. He stood politely and invited her to sit with them. She did so.

“I was hoping to speak to you,” she said. “I noticed… your medallion… Is it… do you mind…” She reached with professional fingers to feel the obsidian pendant, rubbing thoughtfully over the enamel flower. “It IS real, isn’t it? It’s not a copy?”

“It’s real,” The Doctor answered. “It’s a family heirloom. I’m The Doctor… Doctor John Smith. And I see from your name tag that you’re director of special exhibitions. You’re in charge of looking after my Aztec lady?”

“I am,” she told him. “I was also head of the expedition that found her. But… ‘my’ Aztec lady?” She smiled. “We think of her as ours.”

“She was an independent lady who regarded herself as no-one’s,” The Doctor said. “Except of her own choosing. And for her time that in itself made her a remarkable lady.”

“You ARE an expert, not just a tourist. I thought as much. But why didn’t you identify yourself to me… instead of acting like a hoodlum vandalising the exhibit? If you’re interested in making a study of her background, we could arrange a private viewing of the artefacts not on public display. But have you visited the site of her village? The temple was badly damaged by the earthquake, but still remarkable.”

“Yes,” he said. “I’ve seen it. Though not recently. The archaeological dig was something of a surprise to me. But the private artefacts… I would like to see them. Could you make such an arrangement?”

“Give me ten minutes,” Miss Torres said. “Meet me at the exhibition room.” She left them. The Doctor looked very happy. He had the bounce in him again.

“You told her you were Doctor John Smith, and that you were an expert on her Aztec lady and she goes off to arrange for a private viewing?” Wyn summed up the conversation that had gone before. “I’m not surprised. I’ve seen you do that to people before. But I am impressed. You always impress me when you do that.”

They went back to the exhibit ten minutes later. The Doctor watched with an almost pained expression as a group of Mexican school children walked around the glass case, listening to their teacher talk about the process of natural mummification. They all looked at the remains of his brief sweetheart with the same fascination children of that age watch horror films, thrilled by the gruesomeness of it. They none of them saw that she was a beautiful woman. Only The Doctor saw that. He was glad when they all passed on to another wonder of ancient Mexico and left him in peace with her.

“Doctor Smith?” Thalia Torrres returned with security passes for The Doctor and his entourage. She saw that they were affixed to their lapels before she brought them to a code-key locked door marked ‘privado’. That led to a flight of stairs down to the basement of the Anthropology museum, where the real work went on. Here, artefacts were repaired, restored, reassembled in the case of some pieces of Mayan pottery that were the painstaking job of one of Thalia’s colleagues. Here, also, research went on into the artefacts and their significance to the understanding of the past culture of their country.

Thalia Torres brought her guests to the large room where she was working on “La Dama Aztec”. The first thing The Doctor noticed was a computer monitor on which a rather unusual screensaver was running – a series of pictures starting with the face of the mummified lady, and then a number of reconstructions of what she must have looked like, just before her death as a very old woman, and in various stages before then, through handsome middle age, right back to when she was a young woman. The Doctor gave an emotional cry as he watched the sequence several times.

“You found out what she looked like,” Wyn said to Miss Torres. “You took measurements of her bone structure and then computer modelled her face. Then used software to work back her age.”

“Yes.”

“Wow,” Stella murmured.

“It’s magnificent,” The Doctor said. “But not quite right.” Then to Miss Torres’s horror he opened the face manipulation programme and selected a picture of Cameca when she was in her early fifties. He tweaked it in small but strangely significant ways, a slightly higher cheekbone, the chin, eyes, a little different, the forehead and the way the hair fell upon it. “Yes,” he said. “That’s how she looked. Work the other pictures from that template.”

“How could you possible know that?” Thalia Torres asked. “We were guessing at best. Nobody really knows what any of them looked like. Even the statues and portraits of the kings are what later artists imagined.”

“I know,” The Doctor answered. “But believe me. This is her. This is Cameca.”

Thalia Torres’s eyes opened wide.

“How did you know that was her name?”

“How do YOU know it?” Jamie asked. “It doesn’t say anything on the display upstairs.”

“We haven’t used any of the scrolls in the public display,” Thalia answered. “I’m not sure we ever will. If it was up to me, certainly not. They’re just too… too…”

“What?” Stella asked. “Are they really messed up, damaged?”

“Far from it,” Thalia said. “The parchments are beautifully preserved. I’ve been working on them for months, translating them a few at a time, trying to put them in chronological order. But I don’t think I could…” She laughed softly. “I’m a professional. I should be objective and unemotional, uninvolved. My research is into lives that ended more than half a millennia ago. That shouldn’t be hard. But I would rather not have the Lady Cameca’s letter’s on public display because they’re too beautiful and too private.”

“Let me see?” The Doctor asked. Thalia looked as if she would refuse, but she caught his eye. There was a long moment in which she seemed unable to turn away from his gaze, then she nodded and brought him to a table that was sealed inside a humidity controlled screen, with special lights to protect the parchments that were laid out. There were a dozen or so of them, all inscribed with Aztec pictographic script.

“These are only a few of them,” Thalia told The Doctor and his friends. “We found more than five hundred individual pieces of parchment in a wooden box inlaid with obsidian. They are letters, written by the lady. Except the letters were never sent. She wrote them once a month at least, and kept them hidden. She did it for over fifty years, until she died at the age of 108.”

“Wow!” Wyn exclaimed. “That must have been a good age for her time.”

“It is,” Thalia confirmed. “It’s nearly thirty years longer than the life expectancy of a present day Mexican citizen. In her own time, she was already considered elderly when she began writing these…” Thalia paused and noticed that The Doctor was reading them all intently, and quickly, as if Aztec pictograms were his first language. “They’re mostly love letters. She wrote them to somebody who was no longer in her life, but which she obviously longed for. She writes in some of them of thinking of him, never forgetting his face.”

“Is there a name for her lover?” Jamie asked.

“There is, but we’re puzzled about it,” Thalia answered. She reached for a computer screen next to the sealed table and brought up photographs of the letters. She zoomed in on one pictogram that appeared often in the letters. “Well, this is obviously the name of the lover. But the word doesn’t make sense in the context of her life.”

“Why?” Wyn felt she had to ask. Though she had a very strong suspicion, judging by the look on The Doctor’s face.

“Because…” Thalia began. But The Doctor gave a sudden cry of astonishment and called her to his side. He pointed to one of the parchments on the table.

“This one,” he said. “She writes to her… her lover… telling him all about something that happened. She was walking in the Garden of Peace in the early evening when something fell from the sky. She called it a fallen star…. She says it was shiny like a jewel, but bigger than her hand, and it seemed a thing of magic. She said she felt its power.”

“Yes,” Thalia said. “That’s another thing that makes me reluctant to present these to the public. I can just imagine what nonsense would be said. Even one of my own colleagues joked about it. An alien artefact, he said it was. And the public would be bound to make up stories of that sort. She refers to it again many times. She was convinced that the ‘fallen star’ was the reason for her long life. She said it gave her vitality.”

“Really?” The Doctor looked interested. “And do we know what happened to it? Her fallen star?”

“It’s here, too,” Thalia answered. “Come here. You might as well see the rest. I don’t know why, but I have a feeling you could answer all the questions that remain unanswered.”

“Possibly I could,” The Doctor told her. “But then what would you do with your time? Searching for the answers is your reason for living, Thalia.”

“It’s my job,” she said. “I’m an anthropologist.”

“It’s more than your job,” The Doctor insisted. “It’s your passion and your obsession, isn’t it? You’re one of those rare, wonderful, single-minded Human beings who spend their lives pursuing questions, searching for the truth. And the chase is what it’s all about, not the finish.”

“You’re…” Thalia looked at him and seemed to be choosing her answers to him. “You’re a very strange man, Doctor Smith. And yet…” Then she shook her head and became business-like again. She opened a drawer in a strong, steel cabinet and brought out an obsidian box about the size of a box of tissues. She opened it, and her face was lit up by the contents. The Doctor peered in at it.

“Have you touched it?” he asked her.

“Yes,” she replied. “It has a sort of tingle, as if it was charged with energy. The glow… I don’t know how to explain it. Except the joke answer – that it’s something alien. And that I can’t accept. It ISN’T a fallen star, obviously. They had a different idea of what the stars are, of course. She could have believed it. But it isn’t. Nor is it a meteor of the usual sort. I don’t know.”

The Doctor looked again. It was an irregular geometric shape, with many facets. It was pure white like a diamond, but it didn’t just reflect light. It really did have a light of its own inside. And it was utterly beautiful.

“Miss Thalia Torres,” he said. “I am sorry, but I can’t give you any answers about this. I am afraid you will have to work them out for yourself.”

She nodded as she tried to hide her disappointment.

“We have taken up too much of your time, with such a poor return on the investment,” The Doctor said. “We should let you get on with your work. But thank you, Miss Thalia Torres. What you have shown me has been illuminating and inspiring. Your questions remain unanswered. But you still have the thrill of the chase. And I really do think that is more valuable to you in the long run.”

She brought them back to the public part of the museum and shook hands with them all before going about her proper business. The Doctor smiled as he watched her go. His friends looked at him curiously.

“Doctor… you DID know something, didn’t you?” Wyn demanded. “About that ‘fallen star.’”

“Oh, yes,” he answered. “I wish I could have told her, but it would have been too difficult for her to comprehend. She’s a bright woman. And she has passion. But she’s not ready for that. Nobody on this planet is. Which is why…”

He stopped mid sentence and his expression changed again. They all, especially Wyn, recognised his new mood as ‘enigmatic’. They knew they’d get no more out of him for a while. They shared Thalia Torres’s frustration and disappointment, but resigned themselves to it. The Doctor nonchalantly reminded them that there was a lot more of the museum to see and they rallied themselves to enjoy what they had found fascinating, so far. It was all the more interesting because of The Doctor’s anecdotes that went so much further than the information in the brochure or on the display panels.

When being indoors palled they went to look at the outdoor exhibits, including a garden which faithfully recreated the type of plants grown by the Aztecs. The Doctor got quite excited there, telling them about the garden Cameca had tended, and expanding on what he had said earlier about the properties of some of the plants, the least dangerous of which seemed to be Nicotiana Tabacum – the tobacco plant. Later, they watched a colourful display of Aztec dancing which King Nezahualcóyotl would have loved and an exhibition of hand to hand fighting recreated from pictograms and paintings. The Doctor said it was almost right and praised the effort.

They had tea in a café in the Chapultepec Park and spent an hour before dusk near the Spanish castle at the top of the hill that had replaced the royal palaces of the Aztec kings just as Spanish lifestyles had replaced the Aztec. They viewed a monument to the Niños Héroes, a group of very young cadets who had fought to the death against a stronger American invading army. Wyn pointed out how many times she had seen the Alamo as the Saturday afternoon film and wondered at the fact that there were no movies about this opposite view of heroism. But for the most part, they were all drawn back to the pre-Columbian history that centred on the Museum of Anthropology.

“The museum closes soon,” Wyn reminded The Doctor. “Do you want to go and see her one last time?”

“No,” he answered. “I’ll do that later. Let’s watch the sun go down on Mexico City from the top of the Grasshopper Hill and then I’ll make supper. After that… there’s something I have to do… I will probably do it alone. I don’t want to get you lot into something you shouldn’t be involved in.”

Again, he got enigmatic on them. Again they knew there was nothing to do but wait to find out what was going on. They enjoyed what was a very attractive sunset over the park and the suburbs of Mexico City and then walked back to the TARDIS along subtly lit paths in the park that was enjoyed in summer long after sundown. The Doctor did, indeed, cook supper and they enjoyed that, too. They teased out from him the story of what happened on his trips to pre-Columbian Mexico, including the tale of his adventures in Cameca’s village. Then, when he was certain that the museum would be quiet, he told his companions what his plan was.

They were astonished.

“You’re going to break in and steal the ‘fallen star’?” Wyn summed up the plan in a single line. “Why?”

“Because it doesn’t belong on Earth. It IS an alien artefact and it can’t stay here. As long as it was in Cameca’s tomb, hidden, that was all right. If I’d have known, I would have gone and looked for it ages ago. But as it is… it belongs to another race, one who understand how to use it.”

“It’s dangerous?”

“Not exactly. It just isn’t right for humans. I want you all to stay inside the TARDIS. There’s no need for you to be involved in this. Jamie, you’re supposed to be on the side of law and order, and Wyn, Stella, your mother would kill me if I got you involved in a robbery charge. I’m not sure mine would be happy about it, either. But I have to do this. You don’t.”

They protested, but he was adamant. He at least promised that afterwards he WOULD properly explain. And that was the best they could get from him.

He carefully studied a plan of the museum and materialised the TARDIS in the basement near the place where Thalia Torres had stored the ‘fallen star’. He stepped out, thinking how very conspicuous the TARDIS was here, and wondered what it might have disguised itself as if that function still worked.

He found the cabinet. The drawer was locked, of course. But the sonic screwdriver made short work of that. He opened it and found the obsidian box.

“Put that down,” said a voice. The Doctor recognised her accent, but he carried on with substituting an ordinary piece of meteorite for the ‘star’. “I said, put that down. I’m calling security, right now. You should know that they carry weapons at night. I suggest you put your hands up.”

“I'm taking the ‘fallen star’ to my spaceship,” he said. “By the time security get here I’ll be gone.” He turned as Thalia Torres gasped in surprise. “Yes, it’s me. No, I didn’t deceive you earlier. I am genuinely interested in your beautiful Aztec Lady. And I am grateful for all that you did for me this afternoon. But this doesn’t belong here, and I’m taking it away.”

He placed the glowing star in his pocket and put the obsidian box with its less exciting contents into the drawer. He stepped towards Thalia and she stepped back from him, nervously, backing towards the TARDIS, which she obviously didn’t expect to see here.

“Doctor Smith… what is that?” she asked. “Why is it… What are you…”

“It’s my spaceship. Well, time and space ship actually. I would show you around – reciprocal gesture after you showed me your workplace, but I really must be going.”

Then the door opened and Wyn looked out.

“Miss Torres,” she said. “Come inside. The Doctor will explain everything. To all of us.”

“But…”

“Please,” Wyn added. “Come in.”

She looked at The Doctor. She looked at Wyn at the door. She squinted past her at a room that was much bigger than it ought to be. She took a decision and stepped inside. The Doctor followed her and closed the door quietly. He wasn’t trapping her as such, but now that his plan to simply leave with the ‘star’ had gone awry, Wyn’s idea of bringing her in and telling her the truth was as good as any.

She stared around the console room. Everyone did, of course. She stared at K9, at the console, at The Doctor and his friends standing there.

“Your colleague who said it was an alien artefact guessed right,” he said. “It is exactly that. And yes, I’m an alien. This is an alien ship. But there is nothing to be afraid of. Just about every film you may have seen about aliens is totally wrong. You are perfectly safe.”

“The ‘star’…” she said, deciding that the question of the alien ship and alien Doctor could wait. “Why did you steal it?”

“I told you, because it doesn’t belong to you. It doesn’t belong to anyone on this planet. My dear Cameca took care of it, but now I’m talking it back to the people it belongs to. They’re called Kazci. Their planet is…ohhh… approximately ninety million light years from Earth. They are like my own people in one respect. They live very long lives. But mine were naturally long-lived. The Kazci found a technology that lets them prolong their lives. The ‘star’ is actually a Kazci second heart, an artificial one that grants the bearer good health and vitality for maybe two or three times their normal lifespan. This one must have belonged to a Kazci who had an accident of some kind. It was dislodged from his or her body. It fell to Earth to be found by the one pure soul who would not use it for base reasons. And for that we may all be grateful. But now it is time for me to take it back to the people it belongs with.”

“It prolongs life?” Wyn questioned. “You mean…”

“How often have you touched it, Thalia?” The Doctor asked.

“About a dozen times since I unsealed the box,” she answered.

“Then you’ve probably given yourself an extra year of good health. My dear Cameca must have been delighted by such a pretty thing. I expect she couldn’t resist touching it. It gave her health and life beyond her natural years. It doesn’t give eternal life. Eventually nature catches up. She was a woman who lived life to the full, and I can think of nobody who deserved to do so more. But she would have known when it was time to let go. The Kazci know that, too. But Humans, generally, they get ambitious and greedy. If the properties of such a thing were known…”

“But it could be used for good,” Thalia suggested. “People with debilitating illnesses, who need the strength to recover…”

“Another pure soul,” The Doctor said to her. “But it wouldn’t be used for that, would it? It would be sold to the highest bidder, to those who can afford it. You know that it would. Sorry, Thalia, but it’s for the best. Do you see that?”

“I suppose so. But…”

“Do you believe me?”

“I don’t seem to have any choice in that. I am standing in a space ship that is inside a small wooden box in my workshop. All right, Doctor, take the ‘star’. But tell me one thing, before you go… How did you know her name? How did you know what she looked like?”

“I think you know the answer to that, already. You just can’t let yourself believe it. I don’t fit into your parameters. You are used to verifiable facts, provenance, proof. I don’t fit so easily into your view of the world. But… Jamie, remember the question you asked Thalia earlier. We didn’t wait to hear her answer.”

“I asked if there was a name for her lover,” Jamie recalled. “And you said it was difficult. What was that word in Cameca’s letters that seems so out of order?”

“Doctor,” she answered. “She wrote love letters to somebody she called Doctor.” Thalia turned and looked at The Doctor and her eyes widened as it all fell into place. “Oh, you mean… She wrote the letters to you?”

“She never expected – never did – meet me again. She wrote them to herself, a harmless indulgence. But yes, she was obviously thinking of me. So, that’s another of your questions answered. How do you feel about that?”

“I feel… flat,” she answered. “I’ve done so much research and now the answer is given to me. You were right. The chase was what mattered to me.”

“Would you like to get some new questions?” The Doctor asked. “Let me take you on a little trip. Let me show you something…”

He moved to the console and took a few minutes to set a co-ordinate. The TARDIS dematerialised from the museum. Thalia looked at him and wondered what was happening. She looked to his friends for help, but they knew as little as she did about what he was doing right now. Then the Time Rotor indicated that they had reached their destination. The Doctor left the console and took hold of Thalia’s hand. He brought her to the door and threw it open. She gave a soft cry as she saw that the TARDIS was in mid-air, turning slightly.

“You can’t fall,” he said. “There’s a forcefield. But it does allow great views. Do you recognise the city below?”

She looked and gasped again. So did the others when they came and stood with her.

“There’s a model of it in the museum,” Stella said. “Tet… Ten… oh, nuts! I can’t pronounce it now….”

“Tenochtitlan,” Thalia breathed. “It is… it really is. I’m looking down on the island city of the Aztecs… How did we…”

“Remember, I said time machine.”

“Oh, the aqueducts. The… the street layout… the… oh…” She stared at it for a long, long time. Her lips moved in wonder as the new questions The Doctor promised formed in her mind. “Doctor… thank you,” she said.

“Still plenty for you to discover,” he told her. “There always will be. And you’ll always have the enthusiasm for it.”

“Yes, I will,” she said. “Oh, I can’t tell anyone I’ve been here. But I will know, in my heart. Just as I know the identity of Lady Cameca’s lover. I think you’d better take me home now. Or I will burst with excitement.”

He did so, but he did it the slow way. He moved the TARDIS forward in time, a year every ten seconds, and they continued to see the changes to the island city of the Aztecs, until eventually the Spanish arrived and even greater changes came, ultimately destroying that indigenous culture. They saw a Spanish palace replace the Aztec one on the Grasshopper Hill. They saw the centuries turn until they were back to the summer of 2017 and Mexicans of Spanish descent like Thalia were doing their best to remember the culture her own race had done so much damage to.

“As long as people like you keep asking those questions, they’ll never be completely gone,” The Doctor told her as he materialised the TARDIS inside the museum, this time near the entrance to the exhibit entitled “La Dama Aztec”. Thalia turned on just one low light that illuminated the glass case where the Lady lay in peace. The Doctor went to her. He laid his hand on the glass above the preserved body. His friends stayed by the TARDIS door. At last, he was able to have a few minutes quiet reflection and they wouldn’t disturb him.

“Don’t any of you go until I get back,” Thalia said and raced off towards the staff entrance to the basement. When she returned, The Doctor was still at his silent vigil. She waited, too, until he was done.

“You’ll take good care of her, won’t you?” he said to her.

“Of course, I will, Doctor. But… this is for you.” Thalia gave him a CD ROM in a plastic case. “Digital photos of all the letters. Time they were delivered to the one they were addressed to.” The Doctor accepted it with glassy eyes and a choked ‘thank you’.

“You know,” Thalia added. “When I was burning the disc, I glanced at some of the files. I can read them, easily. Is that your doing?”

“That’s a gift from my TARDIS,” he replied. “I think it remembered how to read Aztec, after all. Make the most of it.”

“I will,” she promised. “Goodbye, Doctor.”

“Goodbye, Miss Thalia Torres. Keep on asking those questions.”

He kissed her cheek gently before turning and going into the TARDIS. His friends followed. They watched as he carefully put away the CD ROM and the ‘star’ before preparing for dematerialisation.

“Are we going to that planet where the ‘star’ came from?” Jamie asked.

“Yes, we are, next stop,” The Doctor told him. “A quick trip. Unless they ask us to have breakfast with them. They have such long lives, they know how to make a meal last.” He looked one last time on the viewscreen at Thalia standing next to his Aztex Lady in her glass case before the TARDIS entered the vortex, leaving them behind.

“You know, I knew another Thalia once,” he said.

“Another girlfriend?” Jamie teased. The Doctor laughed.

“No, she was Chancellor of the High Council of Gallifrey. She voted to have me executed. Apologised later, but for a while I was in trouble.”

As usual, his friends didn’t know if he was telling the truth or not. They decided they didn’t care.