The TARDIS wheezed to a stop. The Doctor looked at the viewscreen and frowned. Ace looked at it and shrugged.

“It’s got to be Earth,” she said. “No other species in the universe could possibly have created grey pebble-dash and then decided it would be a good thing to cover every house in a whole council estate with it. No other species in the universe could have invented council houses.”

“I think the spatial location stabiliser is destabilising,” The Doctor said, ignoring her comments about social housing in the late twentieth century. “The date is right, but we’re in the wrong place.”

“Where and when were we supposed to be?” Ace asked. She was used to mystery tours by TARDIS by now. It was no great surprise to find they weren’t where The Doctor thought they should be. “And when and where ARE we?”

“It’s Saturday, July 13th, 1985,” The Doctor replied. “And I was planning to take you to Wembley to see the Live Aid concert. You missed it first time around because you were away on Iceworld, so I thought you might enjoy it.”

“That was a nice thought, Professor,” Ace told him. “Thanks, anyway, even if it hasn’t worked out. So where are we, then?”

“Liverpool.”

“That would be all right twenty years earlier when the Beatles were about,” Ace conceded. “But in 1985... not much to shout about.”

“Interesting thing is, I think the TARDIS did it deliberately. It’s honed in on somebody I met once, a long time ago. I think the TARDIS thinks she needs my help.”

“Somebody does,” Ace commented. Then she hit the door control and dashed outside. The Doctor paused to pick up his hat and umbrella before strolling after her.

The TARDIS was parked on a bridge with the sort of old brick walls either side that suggested a railway ran underneath the road. One side of the bridge was that estate of grey pebble dashed council houses. On the other were nicer looking houses of clean red brick with pvc windows and neat fences around the small squares of lawn that passed for gardens. One of the houses stood out from the others because the garden included a pond with a working fountain and a colourful collection of wind chimes and little windmills that were in perpetual motion and a collection of pottery animals residing among the grass.

It wasn’t Ace’s kind of thing, a bit too cheesy for her liking, but it was a nice, well kept garden. Or it would have been if there wasn’t a fight going on in it. There were six children laying into each other with fists and feet, screaming what even Ace, who was never a shy retiring child, thought was very coarse language for their age. Not one of them looked over ten years old, but the woman whose garden they were destroying was unable to stop them punching each other. She took some nasty hits herself in the attempt. So did Ace as she ploughed in, pulling a boy off another one by the hood of his anorak.

The Doctor took in the scene calmly and then put two fingers in his mouth and whistled. It wasn’t a shrill whistle. Rather, it had an almost musical cadence to it, and Ace felt a strange calmness in her mind at the sound.

It calmed the children, too. They stopped punching and kicking each other and stared around with puzzled expressions. Ace thought they looked as if they had just come out of a trance and wondered what they were doing.

Then all but one of them turned and ran. The one who didn’t was sitting with one foot in the pond and the other twisted painfully. He had a gash on his forehead that was bleeding badly.

“This one is going to need some TLC,” The Doctor said, lifting the child into his arms. He turned to the woman, who was holding the broken pieces of a ceramic tortoise in her hands and surveying her wrecked garden mournfully. “I suggest we all go inside, Samantha. I’ll look after this little one. Ace is a jigsaw fan. She’ll put Mr Tortoise back together again. You put the kettle on and make us all a nice cup of tea.”

The woman opened her mouth ready to ask how somebody she had never set eyes on before, who had turned up in her garden completely unannounced, knew her name. Then she closed it again. She passed the broken pieces of pottery to Ace and led the way inside.

The interior of the house matched the outside for cheap and cheerful ornaments, mostly pottery animals. It was scrupulously clean and smelt of furniture polish, shake and vac and plug in air fresheners. Much to her surprise, Ace liked it. She always thought it was the sort of thing she hated. It was a lot like her own home, where she was always being told not to get mud on the living room carpet and not to put her sticky fingers all over the furniture and not to do this, or that...

Ace hated being told what not to do as much as she hated being told what to do. Houses like this were all about the things she thought she had run away from.

But perhaps she had been away long enough to appreciate the smell of Pledge. Settling down at the dining table with old newspaper over it, a tube of superglue and the broken tortoise she was quite content. Samantha made the tea. The Doctor actually behaved as if he WAS a medical doctor, looking after the injured child. Everything seemed amazingly homely and normal.

Except it wasn’t of course.

“How do you know me?” Samantha asked. “Were we at school together? You must have been in a higher year than me. I really don’t remember...”

“I’ve changed a lot more than you have, my dear,” The Doctor told her. “You look just as I remember you. A little older... but just the same girl I met all those years ago at Gatwick airport, when you were trying to find out what happened to your brother.”

Samantha stared at The Doctor. He looked back steadily. Ace watched him. She was sure he wasn’t actually hypnotising her, but something very close.

“I was twenty-two,” she said. “Doctor... you’re an old flatterer. I’ve changed a LOT since 1967. I’m forty years old, now.”

“I wouldn’t have taken you for a day over thirty-three,” The Doctor assured her. “I haven’t properly introduced my friend, Ace. Ace, this is Miss Samantha Briggs.”

“It’s Mrs Anderson, now,” she said. “My husband passed away two years ago. We didn’t have any children. I teach at the local primary school. I never missed not having any of my own...”

She stopped talking, as if she suddenly remembered she was telling very personal things to one total stranger, and one man who had come and gone from her life eighteen years before.

The Doctor smiled. He remembered a bright brash young woman who wasn’t put off by evasions and obstructions as she joined forces with him and his friends, Ben, Polly and Jamie to track down the body snatching aliens who had taken her brother. She was a little less brash now. Two years of widowhood must have been sobering to her. But he had no doubt that there was still some of that former spirit left in her.

“Did The Doctor find your brother?” Ace asked her.

“Yes, he did,” Samantha answered. “Him, and dozens more people the aliens had kidnapped. It was the maddest time, ever. I never dreamed when I went down to London looking for Brian that I’d meet anyone like The Doctor or have such a mad time. I’ve often thought about it. Every time there’s a film about alien invasions on the telly! I remember that I actually met some real aliens once.”

Ace smiled and wondered if Samantha would be interested in hearing about some of the aliens she had encountered in her travels with The Doctor, not to mention before that when she was on Iceworld. Daleks, cybermen, haemovores, cheetah people, all kinds of scares, crazy adventures.

She couldn’t imagine ever giving all that up, even if it did feel good to sit in an ordinary living room for a little while and drink tea.

She and Samantha both watched The Doctor with the little boy. He was no more than nine years old, and small and thin for that age, even. His arms and legs were stick thin. His hair was dark and looked as if no comb could ever tame it. He had expressive brown eyes. Just now they were expressing tears as The Doctor put a bandage on his sprained ankle and a large sticking plaster over the cut forehead. He didn’t just give first aid. He talked to the child softly, gently, reassuringly and the tears gradually stopped. Ace wondered if The Doctor had ever been a parent himself. He looked surprisingly ‘right’ with the child. Or perhaps he was just a really good doctor in the usual sense of the word.

The child hadn’t said any intelligible word. The Doctor tried to coax his name from him, but there was no response.

“Do you know who he is, Samantha?” he asked.

“No,” she answered. “That’s the trouble. There are too many children around the streets just lately. That’s what all the fights are about. They’re territorial. These new children are moving in on the streets they play on and they don’t like it.”

“They’re just little kids,” Ace pointed out. “None of them were older than he is. You make them sound like pack animals.”

“I know,” Samantha admitted with a deep sigh. “It’s exactly what I mean, though. I teach most of them. In the school over the way, they’re fine. I mean, they have their little squabbles and problems, tears and tantrums. And some of them have problems at home. This is a council estate. There are single parents, unemployment is rife. There’s alcohol and drugs in the house sometimes. But we all work hard for them, trying to give them the best start in life we can. And if you saw them in the class you’d say they were ok. But the summer holidays started last week, and they’re already turning into feral creatures, roaming the streets with no proper play facilities, nothing for them to do.”

“And these extra children...” Ace queried. “Have the council been housing immigrant families in the area?”

“Not that I’ve seen,” Samantha answered her. “There aren’t very many empty houses for them to settle in. Not enough to account for so many extra children. Hasn’t he said anything? Can he speak English?”

“I’m really not sure if he can,” The Doctor admitted. He tried a couple of different languages, including French, German, Spanish, Russian, Roma and Swahili and four languages that originated on planets other than Earth. There was no reaction from the boy at all. The Doctor wondered if he was deaf and tried sign language. There was no response.

“If he can’t tell us who he is, how can we take him home to his mum and dad?” Samantha asked. “Maybe I ought to call the police?”

“No,” The Doctor answered her. “I don’t think that would be a good idea. He looked at the boy steadily and then pulled off the sticking plaster. Ace and Samantha both saw clearly that the cut was gone. So was the bruising that surrounded it. The forehead was clean and white.

“How did he manage that?” Samantha asked.

“His molecules haven’t stabilised yet,” The Doctor answered cryptically. Then he spoke again in another language.

“K’vaoi gtefd feghy?”

This time the boy’s eyes widened in surprise. He didn’t say anything in reply, but it was obvious that he understood.

He jumped up from the chair he was sitting on and bolted for the front door. He tugged at it futilely until The Doctor followed him to the hallway and opened the door. The boy ran for it, turning left towards the railway bridge as soon as he reached the pavement beyond the garden gate. The Doctor watched where he went thoughtfully and then strolled back into Samantha’s house.

“Professor, what’s going on?” Ace demanded. “How did the kid mend so fast, and what was that language? He obviously understood it.”

“That language was Polista,” The Doctor replied. “It’s literally a universal language, spoken in space ports and among freighter crews from all over the galaxy. It was originally spoken by the Pol, the extra terrestrial equivalent of Romanies, but there are very few of them left, now. Their language was their legacy to the galaxy. I should have thought of it before, really. It was obvious, really. Most humanoid species know a little bit of Polasti.”

“You mean that boy is an alien?” Samantha queried.

“That’s exactly what I mean.”

“The Housing are settling alien families in Edge Hill?”

“I’m not sure Liverpool City Council have anything to do with it, but it would appear that you have some immigrants from a more exotic origin than usual.”

“Crumbs!” Samantha remarked.

“Well... it doesn’t seem like they’re dangerous aliens,” Ace commented. “Little kids with runny noses and their socks around their ankles aren’t exactly planning an invasion.”

“Alien kids must have alien parents,” Samantha pointed out. “Maybe they’re the ones planning the invasion.” Then she thought about that a little more. “No, that doesn’t make sense. Besides, who starts an invasion on a council estate in Liverpool?”

“Professor, there’s a kid in the garden,” Ace said, looking up from putting the final piece of the tortoise in place.

“The same one?” Samantha asked, going to the window. “No, that’s Billy Brewer. He lives in Selsey Close, right behind here. He’s a good lad, no trouble.”

“He was one of the kids busting up your garden, before,” Ace pointed out. “I’ve got a bruise on my shin that would match his trainers if anyone wanted to make a case of it.”

The boy didn’t look like he wanted to kick anyone now. He looked anxious. Samantha went to the door and coaxed him inside.

“Is the kid all right?” Billy asked. “They said... somebody said... that we’d done him in. You haven’t called the bizzies, have you, Mrs Anderson? I didn’t mean it. Honest, I didn’t.”

“The boy is fine,” Samantha answered. “But what was going on out there? All of you picking on one child? It’s not like you. You’re not bullies. Why did you do it?”

“Dunno.” The boy shrugged. “It’s like... these new kids... they don’t talk or nothing. They just watch us. We were just having a kick around in Angela Street...”

“I don’t know why you always have to play football in the streets,” Samantha admonished him. “Crown Street Park is just across Overbury Street.”

“Our mam doesn’t like us going over there,” Billy replied. “Anyway, we were at the footy and the kid was watching all the time. Just watching, like his eyes on us all the time. And... we chased him. And... I’m sorry about the garden Mrs Anderson, and breaking stuff and all. Don’t tell our dad, please. Don’t call the bizzies on us...”

“I haven’t called anyone,” Samantha answered.

“What about him?” Billy looked at The Doctor. “Is he a bizzy?”

“Do I look like a policeman?” The Doctor replied.

“No, not really,” Billy conceded. “A bizzy wouldn’t wear such a stupid jumper.”

“I’m The Doctor. Tell me more about these ‘new kids’.”

Billy looked ready to clam up altogether, then The Doctor fixed his steady gaze on him. Billy opened his mouth soundlessly once, then closed it again. Then he started to speak.

“There’s nowt much to tell. They don’t do nothing, except stand around looking. They don’t talk or nothing. They’re just here.”

“If all they do is stand there, why do you want to chase them?” The Doctor asked. “Why all the fighting?”

“Dunno,” Billy replied. “They just... They make us feel... sort of... scared, like... and... angry. It makes me want to... you know...”

Nobody did know. Billy was obviously not short of expression on any other subject. But he found it difficult to explain why being watched by the strange boy made him want to do something that Samantha insisted was quite out of character for him.

“Where do the ‘new kids’ live?” The Doctor asked.

“Dunno,” Billy said again. “Not round our street. Or Falkner or Overbury, neither. Or Chatsworth. I don’t think they live anywhere. They’re just here.”

“Well, they must live somewhere,” Samantha pointed out.

“Not in a house like normal people,” Billy insisted.

The Doctor began a new line of questioning, but Ace again drew their attention to events outside as a crowd of boys and girls charged down the street, clearly chasing a girl. The Doctor was first to reach the front door. Ace was right behind him, with Samantha and Billy close after them. They chased after the crowd of children as they tore along the road towards the railway bridge where they stopped and looked around in confusion.

“Where did she go?” The Doctor asked. The children all looked a little dazed as if they were coming out of a trance. They stared around at their familiar surroundings as if they were unfamiliar. “The girl. Where did she go?”

“Over there,” said a boy, pointing to the wall that separated the road from the railway line below. The wall was too high for most of the children, but The Doctor peered over and noted that it was mostly disused and overgrown. Not more than a hundred yards along the track were the entrances to three dark and uninviting tunnels.

“She couldn’t have,” Samantha insisted. “That’s a massive drop on the other side. She’d be killed.”

The Doctor hooked his umbrella into the broken brickwork and used it to pull himself up on top of the wall.

“Don’t let me catch any of you lot doing that,” Samantha told the children with all the authority of a primary school teacher. “Or I’ll skin you alive and then tell all your mams so they can skin you all over again.”

The warning was necessary. It was a precarious place to stand. The coping was badly worn with grass and moss growing in the cracks and sections of it missing altogether, but The Doctor stood as easily as if he was on a wide pavement and looked down at the deep valley cut into the very rock that Liverpool was built upon. The ground below was mostly overgrown except a line of track going into the tunnel on the far left which looked as if it saw occasional use.

There was no sign of the girl, alive or dead.

He jumped back down again and looked around. The children all looked back at him.

“I think its time you all went home for your tea,” he told them. Ace and Samantha watched in admiration as the children turned and wandered away in twos and threes until Billy was the only one left. “You too, son,” he said.

“Mam’s working the evening shift at the Spar,” he said. “There’s no tea, yet. She’ll bring something from the chippy on her way home.”

The cold hard facts of working class life were obviously proof against The Doctor’s power of suggestion. He regarded Billy for a long moment and then reached into his pocket to find a Mars bar. Ace was surprised by that. She had never known The Doctor to keep chocolate in his pockets before. It was hardly ‘tea’ by any nutritional standards, but Billy clearly appreciated it.

“Have you been down there on the old railway line?” The Doctor asked him. “Do you and your friends play in the tunnels?”

Billy shook his head. His mouth was temporarily blocked by chocolate and fudge. When he was able to speak again he was more specific.

“We’re not allowed. It’s dangerous.”

“Seriously?” Ace laughed. “A cool place like that to make a den and you don’t go down there. Liverpool kids must be softer than I thought. Me and my mates would have been on it like a shot.”

Billy looked at the cockney teenager in her leather jacket and jeans and recognised a kindred spirit, a child of the streets even if she was much older than he was.

“Nobody goes down there,” he explained. “It’s creepy. There’s black water that pulls you down and drowns you and ghosts that live in the walls.”

“Never heard that before,” Samantha conceded. “But it’s true most of the children stay away from the tunnels. They run right under the school, you know. Crown Street Park is where it all used to come out. The station is long gone, closed down when they built Lime Street way back in Victorian times. But there’s still an old chimney...”

Ace looked around. The old brick wall extended both sides of the bridge as far as the garden fences of the houses on the estate.

“How would we get down there if we weren’t scared of ghosts and water dragging us down?” she asked.

“Broken bit of fence on Ladybower Close,” Billy answered so readily that Ace wondered if the local kids really did stay away from the tunnels after all. The Doctor looked the direction he was pointing then swung his umbrella over his shoulder and strode away. Ace exchanged glances with Billy and Samantha before all three followed him.

The broken fence was in full view of the houses on Ladybower Close. Samantha looked around cautiously before stooping to enter the overgrown area beyond. After all, she was a teacher, a respectable member of the local community, and this was almost certainly trespassing even if there weren’t any signs expressly forbidding them from being there. The land must belong to somebody, she reasoned, British Rail, or the council, maybe.

But nothing would stop her from following The Doctor. It might have been eighteen years since her last encounter with him, and a lot had happened in those years. She wasn’t twenty two any more, and she was a little wary as she picked her way down the overgrown banking, grasping hold of the branches of scrubby bushes for support. But nobody was going to suggest she was past it. Anything a teenager, an eight year old and a middle aged doctor could do, she could certainly do, too.

They reached the bottom without mishap and followed the slightly rusty rails of the still working line back under the bridge and along the cutting. Despite bushes and trees migrating down them, the walls of rock either side still showed the marks where late Georgian navvies in the 1820s had cut through. It was hard not to be a little bit impressed by the thought of such an achievement.

“Yes,” The Doctor remarked with that didactic air that had prompted Ace to call him ‘professor’ from the first time she met him. “It’s the old Stephenson and Wapping tunnels. That’s George Stephenson, of course. His rocket used to come along here on the Manchester to Liverpool railway. Crown Street was the first passenger railway station in the world. I remember the opening day. September 15th, 1830. Rather dull and overcast. The train was late, too. There was a chap in a frock coat grumbling and saying it was all a fad and it would never catch on. They didn’t run locomotives all the way, back then. At Edge Hill they switched to stationary steam engines hauling the carriages on a rope system. I think the chap imagined it was like that all the way to Manchester. No wonder he had his doubts.”

Samantha looked at The Doctor curiously and then decided not to say anything about his historical anecdote. Billy just told him he was ‘bonkers’.

Adults who were ‘bonkers’ were fine with Billy. He was clearly less enthusiastic about going into dark disused railway tunnels. He didn’t actually stop or hang back, but his pace slowed as they came closer. Ace looked into the wider, taller, central tunnel and agreed with him. It wasn’t that she was scared, either, but she felt decidedly apprehensive about it.

The Doctor looked in his jacket pocket and produced a torch before they stepped forward and left the daylight of a July afternoon behind them. Its strong beam illuminated the unlined walls where the same tool marks could be seen in the strata of red, black and white rock. It was cold and there was an odd metallic tang to the air. Rivulets of water tainted with what The Doctor said was probably copper oxide leached from the rock accounted for that.

“Would that be a piece of the old winding gear?” Samantha asked as the torch lit up the rusting remains of something mechanical.

“Looks more like a 1979 Ford Cortina,” The Doctor replied. “The mind slightly boggles at the effort a joyrider must have taken to get it all the way down here.”

They walked on, aware that the tunnel sloped downwards. Their echoing footsteps were accompanied by the sound of the rivulets trickling along under the simple force of gravity.

At one point The Doctor turned off the torch and they all looked up a ventilation shaft at a circle of bright sky far above.

“We’re under the park, looking up through the chimney,” Samantha said with a note of awe in her voice. We’ve walked right under the school playground.”

“No ghosts, so far,” Ace noted.

Not long after they did come to the water. It was dark and they could sense even without going close that it was cold. The Doctor crouched and put his hand into it and declared it to be too deep to wade through. Nobody asked how he could tell that by dipping his hand in. Nor did they dispute the collection of metallic and decidedly poisonous minerals he named that were in the water.

“And it has a colony of Greffles in it,” he added, pulling his hand away very quickly.

“It has what?” Ace asked.

“Greffles. They’re a rather nasty aquatic species from the Alterian sector. They really would pull down anyone silly enough to try swimming in there. Quite how the children got to hear rumours about that, I don’t know. But they’re well advised to stay clear.”

“You’re joking!” Samantha looked at the water in alarm. It looked more or less still except where the rivulets fed it. But it was dark and oily and she couldn’t see below the surface. Anything might be down there.

“They’re aliens?” Ace queried.

“Very alien,” The Doctor confirmed. “But colonies of them pop up on Earth every so often. The Scots call them kelpies and have legends of them haunting lochs and drowning people. I’ll pop a note off to U.N.I.T later. They’ll send a decontamination unit around. Can’t have that sort of thing in the middle of a city. Too dangerous by half.”

“That’s nasty, but not what we’re looking for,” Samantha pointed out.

“That’s why we’re going to go back and look in the other tunnel,” The Doctor told her. “It’s all uphill going back, I’m afraid.”

“What? You think anyone here is afraid of a bit of a hard slog?” Samantha asked him. “Let’s get on.”

She marched ahead determinedly. Ace watched her retreating back admiringly.

“How come you never took her with you in the TARDIS, professor?” she asked. “Seems to me, Samantha has what it takes.”

“Back then, I never really offered to take anyone in the TARDIS. They generally ended up with me by accident or because they had no other choice. Samantha had choices. She had her life before her. She didn’t need it plunging into disarray.”

“I like disarray,” Ace told him. “I’m with you for as long as you want me. I can’t imagine not wanting to travel in the TARDIS.”

The Doctor smiled wryly. At some point almost all his companions had said that. But sooner or later they found a good reason to move on. The time when he met Samantha at the airport had been the parting of the ways with Ben and Polly. They went back to what was familiar and normal to them. One day, even Ace, who craved adventure, would decide it was time to move on.

“Well, she hasn’t tripped and sprained anything yet,” he said. “Nor have you. That’s the mark of a good Time Lord companion.”

“Cheeky get!” Samantha called back. “I heard that. Do I look like anyone’s damsel in distress?”

“Certainly not,” The Doctor replied. “Nor is Ace. Two of a kind, you are. But go carefully, all the same.”

They all took it carefully as they negotiated the 1:48 gradient back up to the entrance to the tunnel. Samantha reached it first, and waved to the others to approach quietly. As their eyes became accustomed to the brightness of a July afternoon they saw why.

“More of the new kids,” Billy commented about the three youngsters who were approaching. “Where are they going?”

“They’re going into the Stephenson Tunnel,” The Doctor answered. “Where we were planning to go next. Give them a few minutes, then let’s see what they’re up to.”

They all concealed themselves inside the entrance to the Wapping tunnel until the mystery children were long out of sight, then The Doctor led the way. The Stephenson tunnel had been closed off with some British Rail steel fencing, but it hadn’t been maintained and it was easy to slip through a broken section. The children were already far ahead. The Doctor put on his torch again, but on a dimmer setting so that it wouldn’t be seen in the distance.

“Wow!” Ace exclaimed, looking up at the ceiling of the tunnel. It was lined with bricks just like the other one, but here thin, strand-like stalactites had formed after years and years of accretion. It was an eerie, yet strangely beautiful sight, and utterly unexpected. “You’d never think we were underneath a major city. That’s really something.”

She was so busy looking up at the ceiling that she took her mind off where she was walking. Samantha pulled her back just before she stepped into a wide, deep hole in the floor.

“What the heck is that?” she demanded, peering into the deep pit. It wasn’t subsidence. The hole was perfectly round and was lined with bricks.

“It goes down to the boiler room,” The Doctor explained. “For the steam engines that pulled the carriages through the tunnel. A big hole didn’t matter to the trains. They just ran right over it on their rails. We’ll just walk around it carefully right now and try to remember where it is for on the way back.”

“Wait a minute,” Ace said as they started to edge around the hole. “Can you hear that?”

“Hear what?” But now she had drawn attention to the problem they all knew what it was.

“There’s a kid down there!” Samantha exclaimed. “He’s stuck.”

“One of the strange kids?” Ace asked.

“Must be,” Billy pointed out. “Nobody from the estate would come down here.”

The Doctor knelt at the edge of the hole and shone the torch down. The hole was vertical for about eight feet, then it turned at an angle. He could see movement just beyond the bend. A small, frightened voice was asking for help, in Polista, the language of the space ports of the galaxy. He was surprised how small the voice sounded. Something about the design of the tunnel must be muffling it. That was why none of his own people had come back for him.

He looked around at his companions. Ace and Samantha were both slim of build, but even so, they weren’t really built for climbing down flues.

“Billy,” he said. “If I help you, can you get down?”

Billy looked down the hole. It looked daunting, but he nodded. The Doctor leaned over and lowered him down as far as he could reach and he jumped the rest, landing nimbly on his feet. He looked up and gave a thumbs up along with a wide grin, then he disappeared around the bend.

“He’s slid down further,” Billy called back, his voice muffled. “It gets narrow. I’ll have to pull him out.”

There were sounds of struggle, then a slithering sound. Billy yelled out.

“I’m stuck, too. I’m in the narrow bit and the kid’s further on. I’ve got his hands. But I can’t turn around.”

Ace looked down anxiously and crouched ready to drop down into the flue herself, but before she did, Samantha climbed in. She held on by her fingers to the edge, then dropped the rest of the way. She stumbled a little but wasn’t hurt. She, too, gave a thumbs up then bent and crawled into the narrower space. Ace looked at The Doctor and then took a deep breath before jumping down after her. She reached and grabbed Samantha’s legs and pulled. Slowly she hauled her back out of the hole, clinging to Billy’s legs. He, in his turn, was holding onto the alien child by both hands. He slithered out after him, dusty and badly scraped, his left leg looking crooked and awkward, but alive.

Samantha and Ace lifted Billy up first. The Doctor reached down with his umbrella as an extension of his arm and pulled the boy up. Then the child came up, Ace and Samantha supporting him carefully until The Doctor had him safely. The two women climbed out together and rested for a moment, catching their breath.

“His leg is broken,” The Doctor confirmed. “But if his species have the regenerative capabilities I think they have, he’ll only be in distress for a little while. We’ll take him to the rest of his people.”

“We will?” Samantha queried. “You mean they’re...” She looked down the dark tunnel. She was sure there was some kind of glow ahead, a green glow that lit the stalactites eerily.

The woman who had been a wife and a schoolteacher, responsible and sensible for so many years thought she ought to stay away from the glow. It was something strange and alien, and probably dangerous. But inside that woman was another instinct entirely. It was the instinct that had taken her to Gatwick airport eighteen years ago, determined not to be put off by lies and evasions. Now it took her towards the glow, apprehensive, quaking in her shoes, if truth be told, but never for a moment considering turning back to the sunshine and normality a few hundred metres back at the tunnel entrance.

They were close to where the tunnel had been blocked when the rails were taken up. The green glow illuminated odd patterns on the walls and floors. It was coming from a curiously round stone, about the size of a football, in the middle of the rubble-strewn floor.

“He wants to go into the light,” The Doctor said, setting the alien child down on his unsteady feet. He hobbled towards the glow and lay down on his stomach. The glow increased and enveloped him and his body began to look less solid. They could see straight through him.

Then he vanished and a vaguely child shaped shadow slid from the glow and along the floor. It slid up the wall, joining the strange patterns there. With some stretch of the imagination the patterns could look like a group of children at play. At least they could if you really concentrated.

Then the green glow intensified again. The shadows and patterns on the walls flickered and almost seemed to be moving.

Three of them were moving. They slid down the wall and along the floor into the glow. They slowly took on Human form and solidified into three youngsters who stood up holding hands. They were the boy who had been hurt in the fight earlier, the girl who had been chased and the boy who had fallen down the flue. His leg was clearly better now.

The Doctor stepped forward and spoke to them in Polasti. The girl replied to him in the same. The conversation continued for several minutes in that language. Then the boy who had fallen stepped towards Billy. He held out his hand and in a halting, stilted English he spoke to him.

“Thank... you... for... helping me...” he managed.

“That’s... ok...” Billy answered. “As long as you’re sound now.”

“Sound?” the boy was puzzled. “I... did not make a sound.”

“No... I mean... you’re leg’s better. You’re sound...”

The boy still didn’t understand.

“English is new to them,” The Doctor explained. “Learning Scouse is another step entirely.”

“Could somebody explain what’s going on?” Samantha asked. “Did we really see him vanish into that light, and become a shadow on the wall... then come back again with his friends?”

“He and his friends are going to come back to your house for a cup of tea and a bit of cake,” The Doctor said. “And while we’re walking, I’ll explain.” He said a few more words in Polasti and the three children nodded. The little girl reached out to hold Billy’s hand. He was too startled to object.

“They’re a race called Noeneghest,” The Doctor said. “Don’t worry too much about how to spell it. They’re alien. It doesn’t really matter where they come from or how they got here. Suffice to say they’re here. They live most of their lives as non-corporeal shadows in dark places like these tunnels. But if they choose they can take on the form of any organic lifeform – in this case Human children – for a short time. I think Billy might be wrong about none of the local youngsters coming down here. At least one boy and a girl must have. The Noeneghest got the pattern of your species from them and started changing. They can last for two or three hours at a time before they have to go back to their own form. That’s long enough to come out into the sunshine and play. But they have three problems. Problem number one is language. They haven’t learnt enough English to talk to the Human children. Which leads to problem number two – Human children with their territorial ideas about the streets they live in, who won’t be friends with these shy little children whose English isn’t very good. And problem number three is a subliminal level of negative emotion in the area around the tunnels. It’s why so many fights have broken out in the streets. It’s caused by the Greffels in the other tunnel. They exude it. The Noeneghest are immune to it, but they’re in and out of the tunnels all the time and it hangs on them. They pass it on to the Human children. It wears off after a bit, leaving everyone dazed and confused.”

“So... what can we do?” Ace asked. “To help them. I mean... we’re going to help them, aren’t we?”

“We are,” The Doctor assured her. “First of all, I’m going to make sure U.N.I.T come down VERY soon, tomorrow if possible, to get rid of the Greffels. That will stop all the fighting. At least the irrational fighting. This is only the start of the summer holidays. There will be plenty of squabbles before school starts again, but that’s normal. Meanwhile, Samantha, you’re a teacher. You can take in groups of them, three or four at a time, a couple of afternoons a week, and give them English lessons. They’re quick learners. It won’t take very long.”

“Yes,” Samantha said in a surprised tone. “Yes, I can certainly do that. If that’s all it takes.”

“Not quite all,” The Doctor answered her. “Billy, your job is to be friends with them. Talk to them, help them learn Scouse. Help them to learn ‘street’. Introduce them to your friends and let them join in your games and learn to be Human children in the streets of Liverpool.”

“Can I tell my mates that they’re aliens?” Billy asked. “And the stuff about the light and everything?”

“Yes,” The Doctor told him. “Yes, tell them. Make it a secret between all you children. Not the adults. They wouldn’t understand.”

“I do,” Samantha contradicted them.

“Samantha is the exception to that rule, of course,” The Doctor added.

“They’re my second alien race,” she continued. “I like them a lot better than the Chameleons. I’ll tell you all about those some other time, Billy. Meanwhile, let’s get back to my place for that cuppa. I’m absolutely parched with all this wandering around dusty tunnels.”

“Milk and two sugars for me, if you please,” The Doctor said. “Just how I like things. A quick adventure and home for tea.”