Julia watched her boyfriend as he fastened his shirt cuffs and combed his hair ready to go out for the afternoon. She was going out, too, but not to the same place. That was the only unusual thing about this Saturday lunchtime.

“I almost wish I was going with you,” she said. “It sounds like a fun trip. All the way out to the edge of the Beta Deltan solar system to see the Vorsted-Gatt comet close up. Although, maybe not so much fun with 3c for company.”

“They’re not so bad when you get to know them,” Chrístõ answered in defence of his most notorious student group. “Anyway, you’re going to have plenty of fun without me. The Earth Federation Ballet in ‘Dance of The Galaxy’! Everyone who has the slightest interest in dance or theatre is talking about it. And Mrs Corr has got premier tickets for your ballet appreciation group. Cal’s taking Glenda, too. In his new car. I think I’m the only one not going.”

“They’re going to be in the Beta Delta system for a fortnight,” Julia pointed out. “We can go to the performance in the Nova Castria Opera House by TARDIS.”

“Yes, we can,” Chrístõ conceded. “Just the two of us. I’ll hire a box. Chocolates and champagne, you looking like a duchess in one of your gowns from Adano-Ambrado, completely outshining me.”

Julia smiled and sighed happily. Then the sound of a car horn outside animated her. She jumped up from the edge of his bed and kissed him quickly before grabbing her coat and handbag and tearing downstairs to meet her friends. As the door slammed behind her Chrístõ slipped on his leather jacket and strolled towards one of the two wardrobes in the master bedroom. It wasn’t, of course, a wardrobe at all. He greeted Humphrey cheerfully as he stepped into his TARDIS and set a short hop to Earth Park, his rendezvous with his passengers for today.

Taking 3c on an out of school excursion in his TARDIS wasn’t something he would have contemplated when he first started teaching them. But they had settled down a lot, now. He thought he could trust them. Besides, they needed something to inspire them.

It had been a shock to him when he discovered none of them were remotely interested in the big events going on in their solar system. He had shown them what he thought was a fascinating presentation about the Vorsted-Gatt comet and they had been completely unmoved. Of course, he realised, not everyone was as enthusiastic about astro-sciences as he was. But he had expected a bit more excitement.

It was Billy Sandler who summed it up for the class.

“What’s the point?” he asked. “It’s just lights in the sky to us. Most of us will never leave Beta Delta IV. The Space Corps only takes the top grade students from Nova Castria. Even the freight service wouldn’t be interested in somebody who needs remedial lessons just to break average.”

Chrístõ couldn’t answer that. Billy was probably right. With the extra tuition to help him overcome his dyslexia he was going to get the marks he needed to have a real choice of subjects when he moved up to the senior school, but even then it was going to be a struggle all the way. 3c, even if they worked hard, were going to graduate from high school with average results and get jobs in factories and offices around the town they were born in. The grand careers that would take them out among the stars were beyond their reach.

And if they didn’t work hard, if they let the lack of prospects get them down, they were destined to work in cafes and bars, drive taxis, clean those offices and factories after the average students had finished work and gone home.

And what use were dreams then? What would a comet passing the outer edge of the solar system matter to them? It was passing them by just like everything else.

“Saturday afternoon, Earth Park,” he had told them. “Dress warm. We’re going on a field trip with a difference.”

The promise of something different excited them. So much so that the maths lecturer complained that they were restless through his double period in the afternoon. But he knew his spur of the moment idea would be worth it.

Cal had volunteered to come with him. So had several of the Chrysalids. But he had turned them down. That was the point. The clever students had their futures mapped out. They had enough excitement in their lives. 3c needed something for themselves, without feeling overawed by the students at the other end of the educational scale.

They were all waiting, wrapped up in winter coats, boots and scarves, by the pavilion where everyone gathered for coffee and pizzas in the summer. It was closed in winter, but the boys sat on the tables, defiant of the norm as usual. The girls gathered in a huddle on the benches. When the TARDIS materialised, appearing briefly as the default box with his Theta Sigma symbol on the front, and then as a park-keeper’s shed, they stood up expectantly. Chrístõ opened the door and smiled widely at them.

“Oh, I remember this!” Helen Cary was the girl who spoke louder than the others as they all stepped over the threshold into the console room. “When we were all hiding from Madame Waterson’s patrols… there’s that room that’s like a virtual reality park. And you took us all home afterwards. I sometimes used to think it was just a dream… it couldn’t have happened like that. But it is real, isn’t it?”

The others had never been in the TARDIS before, but they had heard rumours. Now they looked around in wonder at the room that was bigger on the inside and laughed as Humphrey greeted them all in his own unique way. Chrístõ did a head count to make sure he had all twelve of his students aboard and then he closed the door, smiling like a magician about to do his best trick.

“Mia Robinson, come and take charge of the gravitron meter. It needs somebody with a steady hand and petit fingers. Billy Sandler, you can monitor the parallel ion booster.”

Mia’s eyes widened in surprise. She stepped hesitantly towards the glowing, blinking, amazingly complex console. Chrístõ showed her what she had to do and when. Then he gave Billy his instructions. It mostly involved watching a dial and shouting out numbers. He could see the panic in the boy’s eyes. Literacy and numeracy were his weaknesses. Recognising numbers was as hard as recognising the letters that made up words. Was his teacher trying to humiliate him in front of the other students? Even if he wasn’t, what if he messed up and blew the console apart?

“You can do it,” Chrístõ whispered. “It’s only one number at a time and they stay on screen for at least ten seconds. You can manage. And it’ll impress the others.”

Both processes could be automated. Usually they were. The two sections were at opposite sides of the console and he would need arms like an orang utan to manage them at the same time as the drive control. But he wanted to give the two students who most needed their confidence boosting some small role in their journey.

Everyone else, grab a piece of floor and get comfortable,” he said. “You’ll want to be able to see the big viewscreen.”

They did as he said. The viewscreen was currently showing a snow-covered park. But Chrístõ pulled the drive switch and moments later the view was of Beta Delta IV from space. It was a view they had all seen in pictures, but the idea that they were really there was startling.

“It’s not real,” Stuart Peyton protested. “It’s just a video. Or it’s virtual reality, like that room.”

“Oh, really?” Chrístõ smiled and reached for the door control. “Don’t all rush at once.”

At first nobody rushed at all. Then Scott Miller uncurled himself from where he was sitting and walked towards the open door. He put his hand out and then withdrew it quickly.

“It’s… cold outside,” he said. “But it’s warm here. How…”

“Dimensional relativity,” Chrístõ answered. “The console room is in a different dimension to the space outside. It’s ok. You can’t fall. There’s a gravity shield up.”

Scott moved a little closer to the edge of the doorway. He looked out at the starfield above and below, at the Beta Deltan moon that loomed over them and the planet of his birth looking blue, white and green below. His parents had arrived there twenty years ago by deep space cruise ship, but he had never left the surface of Beta Delta before. It was a heady moment for him.

For all of them. Slowly curiosity got the better of them and they crowded around the doorway looking out. Billy and Mia stayed at their posts at first, but a nod and a smile of encouragement from their teacher was enough. They ran to join the press around the door. Chrístõ checked and increased the shield in case things got too hectic around the edge.

“Ok, come and sit back down again,” he said after a while. “There’s plenty more to see. I’ll leave the door open. But settle down a bit.”

They reluctantly obeyed. Mia and Billy came back to the console. Billy took his role seriously and called out the numbers that appeared on his screen as Chrístõ piloted the TARDIS through the Beta Deltan solar system.

“How fast are we going?” Niall O’Leary asked as he looked out through the open door and then up at the viewscreen. “That’s Beta Delta Five, but we’ve only been travelling about fifteen minutes. It takes sixteen hours in a fast shuttle to get there. And the freight ships take even longer. My uncle is a steward on one of the shuttles. He says it’s the worst job, ever. He’s always travelling and goes nowhere.”

“The TARDIS can cut down travel time,” Chrístõ answered him. He typed rapidly on a keyboard and statistics scrolled down the viewscreen. “I wasn’t intending to bore you all with maths today, but if you are interested, that’s our relative speed. Far faster than the shuttles. There’s the bog-standard information about Beta Delta Five for you, as well. Size, population, rotation of axis. I’m not going to test you, don’t worry. Anyone know the chief exports of BD5, though?”

If he had asked that question in the classroom he would have been met by blank stares. But with the red-brown planet looming large before them hands shot up enthusiastically and copper, sandstone and hardwood were named as the natural resources yielded by the colonists of that planet. Two of the students, Helen Cary and Michael Heddin, mentioned having relatives who worked as lumberjacks in the thousand mile wide mahogany forests.

“But you’ve never visited them? And they’ve never visited you?” Chrístõ thought that puzzling. “Your families arrived on their chosen colony planets and stayed put. They never even travelled within this solar system?”

There were various reasons given. Primarily, it cost money and took time to travel even within the Beta Delta system. Most of their parents were manual workers of some kind or another who simply couldn’t afford offworld trips. There wasn’t any real poverty in the colony systems, but some people were better off than others.

And it hadn’t escaped his notice that most of 3c were children of the lower income families. It was another reason why he wanted to raise their expectations of life.

“Maybe I should organise a few more field trips,” he said. “We could visit some interesting places.”

They looked enthusiastic about that idea for a few seconds. Then they looked at each other and their faces visibly changed back to the sort of disinterested resignation he was used to seeing in them.

“Hey,” he said. “I don’t know what anyone else has promised you, but if I say I’m going to do something, I do it. Tell me what you’d like to see and keep your Saturday afternoons open. On my honour as a Time Lord of Gallifrey.”

They believed him. For the next half hour as they moved rapidly past the outermost colonised planets, they talked about the caves of Beta Delta II, jet-biking on the frozen tundra of Beta Delta VI, and many other adventure activities that were closed to them. Chrístõ decided he would make sure they got to try as many of them as he could arrange.

Beyond Beta Delta VI were three frozen dwarf planets that were unsuitable for Human colonisation. They were called Freyja, Hnoss and Zisa after three goddesses of Norse mythology, simply because the captain of the first exploratory ship to map the system was Norwegian.

Zisa marked the edge of the Beta Deltan system. And it was there, passing through the frozen dwarf’s orbit, that the comet Vorsted-Gatt was now coming into view. Chrístõ told Billy and Mia to sit down with their classmates. He locked off the TARDIS in a safe orbit and came to join them, sitting across the doorway, his long legs outstretched and his back against the guardrail inside the door. The students alternatively looked outside at the full, glorious view of the comet and the viewscreen where the TARDIS database was automatically scrolling information alongside three dimensional images of it. Chrístõ explained as much of the information as he thought his students would manage to absorb without their eyes glazing over.

“It is a particularly large comet,” he said. “Some sixty cubic miles, making it four times as big as the famous Halley’s comet of the Earth solar system.” He refrained from telling them that it had a mass of eight point eight multiplied by ten to the power fourteen. That would definitely make their eyes glaze. Nor did he think they were ready to hear about the three point eight grams per centimetre density. These were the kind of things that he had loved to hear from his grandfather when they were stargazing on the roof of his home on Gallifrey, but even most of his fellow students at the Prydonian Academy didn’t find raw statistics like that palatable. Fortunately, there was no Gallifreyan equivalent to the Human word ‘nerd’ or it would have been applied along with all the other epithets his fellow students had for him. But his head, nevertheless, filled with details like that.

He did try to explain to his students what the mass and density meant.

“You know, of course, that a comet is a huge dirty snowball?” They nodded. That was the easy part. “When you make a snowball and you want it to stay together until it hits somebody, what do you do?”

“Pack it really tight and hard,” Billy Sandler immediately replied. “If it’s somebody you don’t like, you pack it around a rock.”

When the disgusted noises from victims of Billy’s idea of winter sports died down Chrístõ continued his explanation of why Comet Vorsted-Gatt was different from other comets.

“Well, think of this as a snowball that Billy made, packed as tight and hard as he can make it, so that there’s something like ten times as much snow in it as anyone else’s, and its ten times as heavy because there’s almost no air in it, just snow crystals crushed together. This is Billy’s biggest ever snowball, and be glad he’s not about to throw it at any of you. Because it would REALLY hurt.”

They all laughed, including Billy. They looked at the comet, both on the viewscreen and through the open door, with awe, but also with humour because the image of it as a very well compacted snowball was firmly lodged in their minds, now.

“Sir…” Scott Miller said. He stood up and walked towards the viewscreen, staring at the data. “Sir… why has the density and mass of the comet changed?”

“What?” Chrístõ looked up at the screen. “That’s not… the data up there comes from the TARDIS database, which collected the information from the observatory on Beta Delta VI. It shouldn’t….”

“No, but it has.” Scott insisted. “Before it said something about eight point eight multiplied by the power of something else. Now it says sixteen point five times ten to the power of fifty and the density….”

Chrístõ stood up and went to the console. His students watched him quietly. They didn’t exactly know what all the numbers meant, but they grasped that it was important.

None of them knew how important. Even he didn’t realise the full consequences at first.

“The first set of data came from the observatory,” he said. “The second… the TARDIS itself took the measurements automatically while we were talking.”

“So… the comet is even heavier than everyone thinks?” Niall asked. “It’s…. one of Billy’s really big ones?”

“It’s…” Chrístõ looked at the data in front of him and then he understood. “It’s a Billy Special with a rock in the middle. That’s why it’s so much heavier than anyone knew before. The observatory in Beta Delta VI is good. But it’s not as good as my TARDIS.”

He smiled widely. His students smiled back, especially Billy Sandler, who took a vicarious pleasure in having his name linked to the comet in that way.

Then he stopped smiling. This was about more than having a clever computer. He began to type rapidly. He bit his lip anxiously as the screen in front of him filled with projected data based on the new mass and density readings for the comet. Then he stopped typing and took a step back from the console. He was aware of Humphrey under the console, trilling empathically. He knew something was wrong. Slowly, his students began to realise it, too. He looked around at them and swallowed hard. They already looked worried. But he couldn’t hide what he knew from them.

“Sir…” Slowly they all stood up and moved towards him. Mia Robinson left her post by the console and grasped his hand. He felt her fear as a solid, palpable thing, and he wished he had something comforting to tell her.

“The scientists at the Beta Delta VI observatory have calculated the trajectory of the comet as it travels through the solar system. They concluded that it doesn’t go close enough to any of the planets to cause any problems….”

He paused. Nobody spoke.

“But they’re using the wrong calculations. The mass and density that the TARDIS is reading… it alters the trajectory. And… I’m looking at a model right now… a projection of what’s going to happen in the next few weeks…. The comet will pull Freyja and Hnoss out of their orbit and… rip them both apart, turning them into… into meteors hurtling inwards towards the Beta Deltan sun…”

He stopped talking. He breathed deeply and tried to apply the lessons he learnt in Emotional Detachment class to this situation.

But he couldn’t. He was no more emotionally detached to Beta Delta than he was to Gallifrey or Earth. The people here mattered to him. He looked down at Mia Robinson’s hand, still clasped in his and pulled the girl into a tight embrace. He reached out his other hand. He was surprised when it was one of the boys, Gary Marshall, who grasped it and allowed him to hug him, too.

“I’m sorry,” he told them as tears welled up in his eyes. “The meteors… will devastate the inhabited planets… Beta Delta Four… will be laid waste…”

Humphrey had been keening softly under the console for several minutes as the emotions around him polarised. Now his cry was a counterpoint to the screams of grief from the people around him.

For a long time Chrístõ could do nothing but cry with them. His own grief was as deep and all-encompassing.

But he knew he had to pull himself together. He had to be strong, he had to be a teacher, a leader. He was in charge of twelve youngsters who needed him to show them what to do.

“We’ve got to warn them,” he said. “First of all, that’s what we have to do. They have to know.”

He moved around to the communications console and found the videophone code for the observatory. He was answered by a receptionist who found his request to speak to the director of the facility confusing.

“I am sorry, Professor,” she said. “If you want to arrange an educational visit you need to go through the website. We don’t take bookings by videophone.”

“I don’t want to book a visit,” he answered patiently. “I need to speak to the director about an impending disaster that he can prevent if he listens to me and acts fast. Please put me through, quickly.”

That clearly wasn’t happening. After several futile minutes he cut the call.

“They won’t listen?” Billy asked. “But…”

“They’ll listen,” Chrístõ answered as he moved to the computer console. “She thought she was keeping me on hold. But I downloaded all the internal extensions while I was waiting. I can call straight through to the director. And I’m not going to waste time on introductions. I’m feeding this information straight to his desktop.”

A few seconds later, the director of the observatory called him. His eyes were wide with astonishment as he read the data that had appeared on his computer screen.

“This can’t be right,” he said. “Where did you get this?”

“My spaceship is in synchronous orbit around the comet right now,” Chrístõ answered. “I’m getting this information from the source. You know what you have to do, don’t you?”

“If this is correct…”

“It’s correct,” Chrístõ insisted. “You have the facts in front of you. The computer model has an error factor of less than point four per cent. In the next two weeks, Freyja and Hnoss are going to break apart with catastrophic, deadly consequences for everyone. You have to contact the governors of the inhabited planets. You have to get them to initiate their emergency protocols, evacuation procedures. It’s what your observatory is there for. To be an early warning system for just this kind of eventuality. Do what you have to do.”

He completed the call and sighed a deep sigh. He looked around at his students. They looked worried, still. He remembered what so many of his fellow teachers had said about 3c. They were the dullest children in the school, with no imagination, no understanding of anything outside of comic books and glossy magazines.

They were wrong. The collective imagination of 3c was working overtime. And they understood fully what was going on.

“It’s still going to happen, isn’t it?” Judy Knox said in a quiet voice. The comet will still break up the planets. And our homes will still be destroyed. Everything… will be gone.”

“We’ve given them time to evacuate the people,” Niall added. “People will be safe. But…” He swallowed hard and tried not to give in to tears again. “My dad… works at a stud farm… the horses… I like horses… I get to ride them at the weekends… They… they’ll rescue the people… won’t they. The animals… they won’t…”

“Horses are valuable,” Chrístõ answered. “They might… if they can… I’m sorry, I really don’t know. I… can’t think straight. I…”

He pulled himself up mentally. He had to think straight. It was his responsibility.

“I need to get you all home,” he said. “You need to be with your families… preparing for the evacuation.”

“Is that what you’re going to do?” Billy asked. “Evacuate?”

“Yes,” he answered. “I’ll take Julia and her family. They can come and stay with my father on Gallifrey until…”

“What will happen to the rest of us?” Dana Peyton asked. “Where will any of us go?”

“I don’t know,” he admitted. “That will be up to the Earth Federation. They will have to arrange relocation programmes. I might be able to pull some strings. The King-Emperor of Adano-Ambrado is a very good friend of mine. He doesn’t particularly like the Earth Federation, but if I asked him he’d send ships and he’d find a way to help… It’ll be all right.”

“It won’t,” Niall said. “It will be horrible, leaving everything behind… packed into ships… maybe for years…. Like when our parents came here in the first place. And then having to start all over again.”

Niall was right. For most of them that was the awful prospect even if a full evacuation could be completed in time. They would be a burden on the federation, refugees looking for new homes. And in the history of humanity, refugees had never been something they really knew what to do with.

“There’s no other choice,” he said. “We have to…”

He began to initiate the programme that would bring them back to Beta Delta IV in just under fifteen minutes, a fraction of the time it took them to come out to the edge of the solar system.

But as he reached for the drive control, an excruciating pain enveloped him. He screamed in agony and stumbled, clutching at the edge of the console before everything went black.

When he came around, the TARDIS was still in orbit on the outer edge of the solar system. He hadn’t managed to initiate the dematerialisation before he blacked out. He was lying on the floor with a cushion under his head. Twelve anxious faces looked down at him.

“Something is wrong,” he said as he struggled to sit up.

“We know that,” Gary pointed out. “You fainted and a comet is going to destroy our world.”

“I mean… apart from that. I felt… I just had a premonition of my own death… imminent death.”

“What do you mean?” Niall asked. “That’s not…”

“It’s creepy,” Mia told him. “Sir… please don’t. You’re scaring all of us.”

“I know, and I’m sorry for that,” Chrístõ answered them. “But you have to understand. I’m a Time Lord. It’s not just a word. Time… is a part of me. And something in time has changed. There was a flux… and… and because of it… I’m going to die… very soon.”

He tried to stand up, but swayed dizzily. Niall and Stuart reached out to help steady him. He grasped their wrists quite by accident, and by accident he felt their timelines.

“No!” he groaned. “Oh no.” He felt it strongly. They, too, were going to die soon… in a matter of weeks. He could feel it.

He grasped Judy’s hand. It was the next nearest. He felt the same thing. Her life was going to end in a few weeks time.

Everyone was going to die.

“Something is wrong,” he repeated. “It’s not going to work the way I thought.”

“What isn’t?”

He didn’t know how to tell them. He couldn’t tell them. It was too cruel.

“Something has changed,” he said. “Between talking to the director and getting ready to go back to Beta Delta IV, something changed. Our whole future altered. And… I’m sorry. This wasn’t part of the plan. But I have to take you with me… to the future… to find out what went wrong.”

“What should we do?” Billy asked. “How can we help?”

“I’m afraid you can’t,” Chrístõ replied. “This is something I have to work out. The best thing you can all do is sit quietly and let me work.”

Billy looked disappointed. He was treating them as useless children, just like everyone else did.

“No,” he said. “Of course you can help. This console is six-sided. It was designed to have a team of people working on it. form pairs. Take a section each. I’ll tell you what to do. Mia and Billy, you’re with me at the drive control.”

Each of their jobs was small, and some of them were only marginally useful in piloting the TARDIS through the time vortex. But they needed to feel useful. They needed something to take their minds of the gut-wrenching horror they were facing.

The TARDIS came out of the vortex three weeks later. They were still in the same place, on the outer edge of the solar system, but it was a very different view. Instead of three frozen dwarf planets, there was a double asteroid belt of debris, all that remained of Freyja and Hnoss. Beyond it, the comet, itself hardly affected by the gravitational pull of the two lost planets, still continued in its orbit.

“Just as you said, sir,” Stuart Peyton said. “The planets broke up.”

“Does that mean…”

Chrístõ didn’t say anything. He programmed the TARDIS to travel through the Beta Deltan system just the way it did when he brought his students out to the edge for a field trip. Only this time there was no joy in what they saw.

Beta Delta VI, the coldest of the four inhabited planets of the system was in a bad state. A five hundred mile wide fragment of Freyja had smashed into the north pole. The heat was melting the ice cap and the sea was rising. He picked up overlapping communications from the rescue ships that were desperately picking up as many casualties as possible.

Chrístõ felt guilty about not offering the TARDIS for that mission, but he needed to see what had happened to the other planets.

Beta Delta V was burning. A fragment of one of the broken planets had smashed into the centre of the largest continent – the one covered in hardwood forest. The trees burnt. Towns were engulfed. From space it actually looked as if the whole planet was alight. Cary and Michael Heddin whispered the names of their relatives who lived on that planet with sad, small voices.

“There was no evacuation,” Niall O’Leary cried out in indignation. “That’s what they’re saying on that channel. Nobody knew this was happening. Not until it was too late. Nobody had a chance to get away.”

“But the director of the observatory had the information from Professor de Leon,” Kate Waring protested. “He knew. Why didn’t he warn everyone?”

Chrístõ couldn’t answer that question. But he thought he knew, now, just what had caused the flux in time. He knew why he was dead in the near future.

Beta Delta IV came into view and the grief felt by all of them was overwhelming. The planet was dead. A huge chunk of it was missing. The meteor that struck it was the largest of all. It had split the crust and a quarter of the northern hemisphere broke away and became, in turn, another dangerous meteor hurtling towards the sun.

“New Canberra is gone!” Scott Miller said the words that seared all of their hearts. Chrístõ heard him as if from a distance. He felt his legs give way under him and he sank to the floor, shaking with grief and sorrow. Humphrey wrapped himself around him, trying to give comfort, but there was none to be had.

“Julia is gone,” he told the darkness creature. “She’s dead.”

“Shoo… shoolia… Pre..tty Shoo…lia…” Humphrey mourned. Chrístõ cried all the harder as he heard his strange friend’s endearing mispronunciation of Julia. Around him, his students cried, too.

“Sir, what’s that?” Judy Knox’s voice penetrated the fog of unconsolable grief that overwhelmed him. He looked up. She was pointing to something on the viewscreen.

“It’s… the SS Elizabeth Garrett,” he answered. “It’s a hospital ship. It must have come to help. But there’s nobody to help. They’re all dead.”

“Maybe they’re not,” Judy suggested. “Maybe some of them are alive in the hospital.”

It was clutching at straws. But it was better than nothing. A piece of hope to cling to. Chrístõ slowly stood up and initiated a materialisation on the hospital ship.

They stepped out into a hospital corridor just like any hospital corridor in the universe, except this one was aboard a huge space ship. Nurses and orderlies moved about with practiced efficiency. Walking wounded, waiting to be attended to, were sitting on chairs and benches. Chrístõ and his students moved aside as a more urgent case on a trolley was rushed towards the intensive care unit.

“I should help,” Chrístõ said. “I’ve got medical experience. They need everyone who can lend a hand. I can…”

“No,” Mia protested. “Please, sir, don’t leave us. We don’t know what to do without you.”

He was about to respond when he heard his name called out frantically. He turned and recognised Marle Benning. She was wearing pale yellow scrubs with a name tag identifying her as a volunteer ancillary worker.

“Beta Delta Three is undamaged?” he asked. “You’re all ok, there?”

“Yes,” she answered. “But… Chrístõ… I thought you were dead. We all did. When we heard what happened on Beta Delta IV, you… were the first person we thought of, even before our families. And we thought… We all thought… Chrístõ… how did you get out of jail? Did they…”

“Jail?” Chrístõ’s pale face turned even paler. “Marle… Oh… I think I understand… some of it anyway. I didn’t…. I’m not. I think… Look, I know you’re busy, here, but we need to talk. Can we go somewhere?”

Marle brought them to the hospital chapel. A special service was going on, but there was a small oratory beside the chapel itself. They closed the door and it was a cool, calm place that contrasted with their emotional turmoil. Dana and Stuart looked at the crucifix and crossed themselves. Some of the others sat on the benches and prayed quietly. Whatever gave a crumb of comfort at this time, they were glad of it.

“Marle,” Chrístõ said in quiet tones that wouldn’t disturb the much needed calm. “We’ve come here in the TARDIS, from three weeks ago, before all this happened. Time was in flux. Something had been set in motion that led to this disaster, but we were able to bypass it and be here… I think I’m meant to be dead. In your timeline, I am… can you tell me how… what happened three weeks ago when I got back to Beta Delta IV with these kids?”

“That was when you started telling everyone that the planet was doomed. You said the comet was dangerous… density and mass and altered trajectories… You told everyone at the school, you told the deputy governor… the real governor was away. He’s been here, to see the survivors. He’s really upset. But at the time he was offworld at a conference… anyway, nobody believed you. The director of the Observatory said there was nothing wrong with the comet. You called him a liar. You said you’d given him information… He denied it. Then you were arrested for causing an affray… We tried to get you released. There was a campaign at the university. But everyone else said you were mad – they thought you were one of those religious crackpots shouting about the end of the world. But then… You were right, of course. The comet… the meteors. By the time anyone realised, it was too late. They couldn’t even start evacuating. The Director… He committed suicide just before the Observatory was destroyed by the flood waters… he sent a message to say that he lied. He had hidden the information you sent him… because of professional pride. He didn’t want to admit his observatory had got the data wrong.”

“All those people died because of one man’s stupidity?” Chrístõ tried to control his anger. The man responsible was dead, after all. But he thought of Julia and her family, Cal and Glenda, everyone at the school, and millions of other people he didn’t know, whose lives mattered to him.

He thought about his own death, locked in a prison cell, unable to help himself or anyone else. It wasn’t how he ever imagined dying. He thought he would go down fighting at least.

“I’m sorry,” Marle said. “I’m so sorry, Chrístõ.”

“There’s nothing for you to be sorry about,” he told her. “It was my mistake. I thought it was better to let the Humans handle this their own way. I… was thinking like a Time Lord… thinking that I shouldn’t interfere. The Beta Deltan authorities had their emergency protocols. They knew what to do. Only… they didn’t. So… So I should have acted. I could have… I could have saved everyone. Julia… I’ve lost her… because I thought like a Time Lord… but I didn’t act like one. I didn’t remember that I am superior to humans… superior in strength, intellect, morality… and that I COULD have saved everyone.”

“How?” Marle asked. “Chrístõ… you’re amazing. You’re the most amazing being I have ever met. But even you can’t fight a comet… Nobody could.”

“Yes,” he answered. “I could… I could have. I should have… but I didn’t… And now it’s too late.”

“Sir…” Chrístõ turned slowly and saw Scott Miller beside him. “Sir… can you really stop this happening?”

“I could have,” he answered. “If I’d acted back then… instead of wasting time talking to that fool at the Observatory… But it’s too late now.”

“Why is it? I thought your ship could travel in time. Why can’t we go back and make it right?”

“Because there are rules,” Chrístõ replied. “The Laws of Time. Events have already unfolded. It’s too late.”

“No, it’s not,” Marle said. “Chrístõ… you aren’t even supposed to be here. Not alive, anyway. You’re not a part of these events… surely you can…”

“Oh!” Chrístõ groaned in exasperation. He grasped Marle’s hands tightly for a long moment and then he stood up. “I… am so stupid… superior intellect… but I couldn’t see what was right in front of my face. Marle…” He embraced her quickly. “If I get this right, we’ll never have had this conversation. You won’t be here. This hospital ship won’t be here. It won’t be necessary….”

He kissed her on the cheek and then he turned away. His students looked at him and then they forgot their prayers and moved to join him. Outside the chapel he started to run so fast they had trouble catching up with him. By the time the last of the reached the TARDIS he was already at the console, programming their journey back in time to before the catastrophe.

“Sir… what’s happening?” The students crowded around the console, asking the same question. At first he didn’t answer. Then as the TARDIS entered the time vortex he looked around at them. They all looked terribly young. That was his first thought. They were young, innocent, vulnerable.

“I ought to take you all home first,” he said. “This might be dangerous. It might not work.”

“If it doesn’t work… we’re going to die anyway, aren’t we?” It was Dana who said that. Again, he thought about his fellow teachers who dismissed these children as slow and stupid. But they had all come to the same conclusion.

“I’d rather die trying to do something, than go back home and wait to die in three weeks time,” Stuart said. “At least… it would be over.”

They all agreed with that sentiment.

“So what are we going to do?” Billy asked. “Are we really going to stop the comet?”

“Not stop it,” Chrístõ answered. “There’s nothing I can do about that. But the problem is it’s too heavy, too dense. That’s why it’s dangerous. But if it wasn’t so heavy…”

“You’re kidding!” Again they caught on very quickly. “We’re going to melt a sixty-mile wide snowball?”

“Yes!” Chrístõ told them. He smiled. Now that he knew there was something he could do, the hard-packed snowball of grief had melted away from his hearts. As long as he was doing something he really could smile.


“First of all, by overriding Borusan’s Protocol,” he answered. “It’s a restriction on the TARDIS that prevents it from materialising inside a solid body. That’s a good thing, usually. Because when it materialises, it displaces the solid matter, and usually that’s bad. But this time…”

He gave his students jobs to do. Overriding protocols was, naturally, difficult. He had to fight his own TARDIS to make it do that. With extra hands at the controls, even inexperienced ones taking instructions from him, it was easier.

“Hold tight,” he warned. “We’re going to do it now.”

The engines screamed. The time rotor glowed with white-green light and then dimmed to near black as the TARDIS materialised deep within the fifteen cubic miles of densely packed snow and ice. The hull creaked ominously as that hard packed snow pressed against it. Chrístõ was at least ninety-percent certain that the TARDIS was capable of withstanding the pressure. But the ten percent uncertainty weighed on his mind. He tried not to think about the TARDIS imploding, crushing all of their bodies and leaving them as a piece of organic matter trapped forever in the comet that was destined to kill everyone they loved.

But the TARDIS didn’t implode. The creaking ceased as he did what he planned to do – transfer latent heat from the Eye of Harmony deep in the heart of his time machine to the outside. It slowly melted the densely packed snow around the TARDIS, creating a hollowed out space.

“Got to be bigger, though,” he said. “We’ve got to bring the mean weight of this comet down by thousands of kilos. It’s going to take a while. But we can do it.”

The way he was doing it would have either impressed or dismayed the temporal engineers who designed his TARDIS. They certainly never intended it to do this.

“The TARDIS is collecting the meltwaters on its outer skin, and transferring it by osmosis to the space between the inner and outer skin and channelling it into the condenser vats in the lower levels where water is usually created by combining hydrogen and oxygen molecules. I’ve reversed the process so that the water is turned back into hydrogen and oxygen. The oxygen is being pumped back outside into the bubble while the hydrogen is being fed into the Eye of Harmony – it gives the engines a bit of an extra kick.”

“It’s working!” Scott cried out. “Look. The mass and density readings are falling. It really is working.”

“Yes,” Chrístõ said. “Yes. It’s working. But it will take hours this way. There may be something else I can try. To speed things up.”

What he did was also, technically, not possible, or at least not desirable in a Type 40 TARDIS. He initiated the time machine’s equivalent of a video on fast forward – time travel without the time vortex. He didn’t do it very often. It made his head ache. He was, as he told his students only a few hours ago, a Time Lord. Time was a part of him. Fluctuations in time affected him physically and mentally.

His students didn’t even realise anything was different. The TARDIS protected them from all outside forces, including time itself. But he felt it in his very molecules. It was like the pain and annoyance of a loose tooth magnified a thousand times and spread throughout his body. He did his best not to let his students see how much he was hurting, but Humphrey gave the game away with his empathic trill and he heard their voices calling out to him as if from a distance, asking him if he was all right.

He withstood it for fifteen minutes before he had to stop or collapse like a heap of jelly with every nerve in his body screaming. He gasped for breath and clutched at the console. Then he pulled himself upright and looked at the data on the main screen.

“Comet Vorsted-Gatt,” he read. “Sixty cubic miles of dirty snow with a mass of eight point eight multiplied by ten to the power fourteen… just the way it was supposed to be. I think… I think we did it.”

He ran the computer model of the comet’s trajectory based on the new statistics. It safely travelled through the solar system on its elliptic orbit.

But he wasn’t taking any chances. Not this time. He went to the drive control and set a new co-ordinate.

The TARDIS materialised three weeks later in orbit above Beta Delta IV. Chrístõ opened the door. His students crowded around the threshold looking out at the beautiful sight of their blue, green and white planet shining in the reflected light of their sun. As the TARDIS slowly revolved they saw the comet Vorsted-Gatt harmlessly streaking across the starfield. It was an impressive sight. But even Chrístõ thought he’d seen enough of it for now. He closed the door and set their course back to the afternoon of their field trip.

“Nobody will ever know, will they?” Billy said to him. “We… all of us.. helped you to save the whole Beta Delta system… save everyone. And they won’t know anything about it. When we go back… we’re just 3c again.”

“You’ll know,” Chrístõ told him. “And I know.”

He looked around at them all. They looked back at him. Nobody needed to say anything else. They understood each other.

“So… next Saturday, jet-biking on Beta Delta VI. Anyone mind if I bring Julia along? If I keep ignoring her on the weekends she might decide not to get engaged to me, after all.”