The Doctor stepped into his meditation room and sighed contentedly as the peace of it overwhelmed his senses. He let himself relax before settling himself in the centre of the inlaid representation of the Seal of Rassilon. He sat in the cross-legged, straight-backed position he had learnt as a boy from the old meditative monks who lived on Mount Lœng in the province of Southern Gallifrey where he grew up. He spared them a thought as he always did when he entered into a meditative trance. They, after all, had taught him how to do it.

He reached out and looked for the souls above him in the house. His wife, soon-to-be-daughter-in-law and granddaughter and his baby son were in the drawing room. His daughter and great-granddaughter were playing in the nursery above. He easily picked up their telepathic conversations. It was mostly about dolls. Just what a four year old and an eight year old should be thinking about. His eldest son was in his study, hard at his constituency work.

There were Humans in the house, too, of course. The butler, Michael and his wife, in their own private drawing room, the two maids having a cup of tea in the kitchen and gossiping as young women do. The house was peaceful. All was as it should be.

“Granddad!” He smiled as he let his mind reach further and caught the thoughts of his two great grandsons. “Where are you?”

“At home,” he said. The phrase still felt a little unusual for a man who for a long time didn’t have a home. But it had a nice feel to it when he said it. “Where are you two?”

“We’re just taking the TARDIS out for a spin. What do you think about Metebelis Three for an afternoon’s outing?”

“Bring bug spray and radiation detectors,” he told them. “And see if you can find one of the famous blue crystals. It will save you having to remember to buy your mum a birthday present.”

“Oops…” He laughed as he heard the sound of two guilty consciences remembering the date.

“Have a good trip,” he told them and left them to it. He reached out further, looking for more telepathic minds to connect to.

“The Children of Israel.” The phrase had stuck in his mind to describe the group of Gallifreyan refugees he had brought to make a new life for themselves on Earth. The analogy with the exiles of the Old Testament of the Human Bible was appropriate. He had freed them from slavery and brought them to the Promised Land. Christopher had risked his reputation and more to arrange new identities for them all and now they were scattered across the British Isles in family groups, starting new jobs, in new homes, fitting in with Human society.

But they looked to him as their leader. Even the oldest among them was younger and less experienced than he was, and he did feel as if they were one great extended family over which he was patriarch. They had all of them reached out to him in the first confusing days when they weren’t sure how they ought to behave in their new communities. He had learnt most of their names. They, of course, knew his. But most of them simply called him – ‘father’.

The children, especially, reached out to him. And their gentle thoughts were ones he looked forward to touching upon. He liked the feeling that they all trusted him implicitly and hung onto every word he said.

They gave him a purpose in his life. Of course he had always had one, but he WAS, technically, supposed to be retired now. He wasn’t supposed to be out there righting wrongs in space and time. Chris and Davie were learning to do that now. He, meanwhile, was what he had always been, one way or another, all his life.

A teacher.

Because his young Israelites were the future of the Time Lord race. They WERE part of Rassilon’s vision of that future, albeit a part he had neglected to mention. And as there was nobody else who could teach them to be the new Time Lords, it fell to him.

It was just like when he taught the twins, of course. Except this time he had about fifty of them, aged between twelve and sixty years of age, the children and young adults of his species. But the principle was the same. He only needed to get their attention, quieten their minds, and then transmit the lessons to them in ten minute bursts of condensed information.

This was their first lesson. The first step towards fifty new transcended Time Lords that would mean his race truly WAS restored. It would take years yet, but he had those years to give to them.

“We’re ready, father,” the gestalt voice answered when he called. He sighed happily and began.

Chris and Davie Campbell smiled as they heard that voice in their own heads.

“He seems happy.” Chris said. “With a new bunch of pupils to teach.”

“Yeah,” Davie agreed. “And he’s off our backs meanwhile. We can REALLY do as we please.”

“He WAS right about the Thermic Torpedoes, though,” Chris added.

“Yeah, I suppose so,” Davie grudgingly conceded.

“You didn’t mean it, did you? About him being ‘on our backs.’”

“No,” Davie admitted. “I kind of wish he WAS still there, teaching us, guiding us. We’re on our own now. He’s got so many others to think about. Vicki and Peter are his children now. And… the Israelites as he calls them.”

“No,” Chris told him. “If we need him, he’ll always be there for us. We’ll ALWAYS be his children.”

“Let’s try NOT to need him,” David decided firmly. The realisation that they were no longer under their great-grandfather’s guidance was frightening. But at the same time he knew it was the chance he had longed for. “If we keep on getting into trouble and having to call on him to bail us out, he’ll think we’re not ready to be full on Time Lords.”

“Good point,” Chris said.

“So…. Metebelis Three.”

“Was he kidding about the bug spray and the radiation detectors? Chris asked as they came into orbit above the planet.

“Maybe about the bug spray,” Davie answered as he checked the environmental controls. “But there ARE residual pockets of radiation on the planet. We’ll need to wear hazmat suits and check the contamination levels regularly.” He looked up. Chris was looking nervous. “Maybe we ought to have picked somewhere with sunshine and sand and no lower age limit at the cocktail bars?”

His brother laughed, but they both knew they wouldn’t do that. The reason they had wanted their own TARDIS was so that they COULD find adventure, excitement, danger, and fight it just as their great-grandfather had always done. But on their own terms. Using the gifts they had.

“Wow!” Chris said as they stepped out onto the desolate but strangely beautiful planet. He looked back and noticed that the TARDIS had disguised itself as a rock formation. Where the door should be a line was merging seamlessly into the craggy surface. When he looked closer he noticed a very small hole that MIGHT be a keyhole and a Ying Yang symbol etched into the rock - The TARDIS symbolising its twin owners.

“Wow,” Davie echoed as they stood and looked around. The first time he had piloted his own TARDIS to an alien planet without any supervision. He was feeling rather proud of himself.

“A blue sun?” Chris queried. “That is seriously weird. It IS really blue isn’t it? It’s not just some kind of light filter in the atmosphere.”

“No, it was blue from orbit, too,” Davie assured him.

“Every other star I’ve ever seen is made up of hydrogen and burns some shade of yellow-orange, depending on how old it is and how pure it is,” Chris said. “Earth’s sun is bright yellow, and Granddad showed us what Gallifrey’s sun is like. That’s red-yellow because it’s an older star than the Earth one.”

“According to the databank, the primary elements in the Metebelis sun are Helium and Lutanium. That’s one of the rarest elements in the universe. They haven’t even added it to the periodic table on Earth. They both give off blue heat and light from the nuclear fission that is constantly happening in a star’s life. Blue sun, blue planet. And apparently the most fantastic blue crystals.”

“Birthday present for mum.” They both grinned, though in the hazmat suits they couldn’t see each other doing so. They felt it telepathically. They talked telepathically, too. Though they were so used to doing that they hardly realised they were doing it.

“So what IS the Lord and Master up to today?” Susan asked. “I thought he might at least come and say hello to me. I bet he’s forgotten it’s my birthday.”

“He’s in his meditation room,” Rose said. “I tend to leave him alone when he’s in there. At least he’s in the house, and not a hundred light years away in the TARDIS.”

“He keeps The TARDIS IN the meditation room,” Susan pointed out. “Are you sure he doesn’t sneak off somewhere when you don’t know it?”

Rose laughed. “Yes, I’m sure. I know he DOES go off sometimes. But he usually tells me he’s going.” She sighed. Susan noticed it.

“I was kidding about that,” she said. “There’s no need for you to feel neglected by him. He loves you.”

“I know he does,” Rose assured her. “I just…” She hugged Peter. He was half asleep, looking up at her with his deep brown eyes. His father’s eyes, she thought. Though in fact, his father had slate grey-blue eyes. Brown were the default colour of the family line.

“I love my kids,” she said. “But I wish I could be out there with him again. The thrill of the chase. I loved it as much as he did. I think… now and again… we have GOT to be the people we used to be. Or we’ll both go nuts.”

“I think that’s where we differ,” Susan said. “I never missed that. I missed HIM. But I never missed running for my life from Dalek death rays and creatures from the pits of hell. And I like knowing that grandfather is in the same house as me, and safe. But really, there is no reason why you shouldn’t… If that’s what you want. You could get a nanny to look after the children. You can afford it, after all.”

“I don’t really want any more servants in the house,” Rose told her. “It’s too much having to guard everything we say in case we let slip that we’re not… not normal Humans. I don’t need a nanny noticing that Peter has two hearts and no tear ducts and… and alerting those Pure Earth nutters to us or something.”

“Doesn’t have to be that way,” Susan considered. “He could get one of his ‘children of Israel’. They all adore him. I’m sure any one of them would love to be nanny to Peter and Vicki.”

“No. He said he would never have one of them as a servant in his home. He says they have served him and his kind all their lives. And it is time now for them to be masters of their own destinies.”

“Yes,” Susan considered. “Yes, he’s right about that. It would be wrong. Funny, but I never thought of the servants in that way when I was a little girl. They felt like part of the family. My nursemaid was such a sweet lady. But, of course, there was a horribly rigid caste system on Gallifrey. We were in the highest reaches of Time Lord society, and the servants were right at the bottom. We can’t have that in our new future.”

“I guess he’ll have to build another baby seat into the TARDIS so we can go off on our adventures as a family unit,” Rose laughed.

“So what happened here?” Chris asked as they hiked across the desolate landscape. “There doesn’t seem to be any life here at all.”

“Granddad happened,” Davie said. “And it happened to him.”

“Huh?”

“There was something really bad here. Something evil. And he fought it. He won of course. Because he always does. But that time it cost him. And it cost the planet, too. The thing that happened here… It’s the reason he had to regenerate one of his lives.”

“Wow. But how come you know that and I don’t?”

“He talks to me, too, you know. Just because you read his dreams and have those long chilled out conversations with him when everyone else is asleep – he talks to me at other times. When we’re doing the engineering stuff together and you’re tuned out thinking of clouds or whatever it is.”

Chris ignored his brother’s gentle gibe at his meditations. He knew he didn’t mean it unkindly.

“Granddad hardly ever talks about his regenerations to either of us,” he said. “Though I know he’s had to do it eight times since mum was born.”

“Well, he wouldn’t. I mean… must be strange. Dying. And then… being alive again. And remembering dying.” Davie shuddered. Chris felt it and agreed. Neither could quite fully grasp the full horror of it, but their imagination and their empathy was strong enough to know regeneration had to be the worst possible experience.

“Worse than dying,” Davie concluded. “Because once you’re dead, it's over. No more pain.”

“That’s one part of being a Time Lord I’m in no hurry to find out about,” Chris said.

“Need to be five hundred or more anyway. The regenerative gene isn’t fully operational until then.”

“I don’t want to think that far ahead,” Chris admitted. “I’m seventeen. Dad says seventeen going on seventy, with too much happening in my head. And he’s maybe right. But I DO want to be seventeen for a while yet. I don’t want to think about being five hundred.”

“It's scary,” Davie agreed. “You know why, don’t you?”

“Because most everyone we know will be dead long before then. All our friends, everyone we know who isn’t descended from Gallifrey, will be dead by the time we’re a hundred years old, let alone five hundred. And it’s scary to think we’ll still be there when they’re not.”

“I suppose that wouldn’t be a problem on Gallifrey where EVERYONE lived longer. It’s only because we were born on Earth.”

“I’m glad we were. We’re alive.”

“We’ll be the first Earth born Time Lords when we transcend. That’s something, anyway.”

“Yeah,” Chris agreed. “So, anyway, blue crystal. Where do we find one then? I hope you know, because I can’t feel any life signs at all on this planet. There’s nobody to ask directions.”

“Nobody to stop us getting the crystal, either.” Davie consulted the electronic map on the hand held device he carried and then took out his sonic screwdriver and took a reading from it. “Blue crystals are in the caves of the blue mountains,” he said. “Thataway.”

“Blue mountains!” Chris laughed. “Do you think the people who named this planet’s topography lacked imagination?”

The Doctor laughed with them, though they didn’t realise it. He hadn’t quite let go of the connection with them when Davie made that comment about him being ‘off their backs’. He wasn’t offended by it. It was true. He DID have the urge to protect them and guide them, and he had to let them have their own way now. He’d taught them everything he ever knew, except how excruciatingly painful it was to have every molecule in your being re-arranged into a new body on the point of death. They would know that in their own time. With luck they would be as old as he was now before they had to face it.

Meanwhile, Davie was right. It was frightening to be out there on their own, to be adults in an adult world now, with nobody to call upon. But that was the way of it. And they WERE ready.

He cut the telepathic link. They didn’t need him eavesdropping on them.

They were all right. Metebelis Three was uninhabited. The Human survivors of the radiation burst that had caused his third regeneration evacuated the planet. The spider creatures were destroyed in the blast. It was a barren waste now, albeit a beautiful one that still had those fantastic crystals to be found in the mountain caves. A fairly non-hazardous challenge for the boys to cut their teeth on in their first unsupervised field trip.

They were fine. His new pupils had managed their first lesson well enough and he’d had enough feedback from them to know they understood what he was teaching them. His immediate family were peaceful still. He smiled and stretched and then let himself drop down into a deeper trance where he could let go of himself and let his body and spirit be renewed together.

It was a hard hike up into the Blue Mountains, especially in hazmat suits. But they were determined to be up to the task. They wanted to tell their great-grandfather the details of a smooth field trip when they got back.

“Something nasty happened here,” Chris said. “Look at the way the rocks have been metamorphosed.”

“A lot of heat,” Davie agreed. “Some massive explosion.”

“Granddad?”

“Only if he lost his temper REALLY big time!” Davie joked.

They both laughed. They had not experienced their great-grandfather’s full wrath very often, but when they did they had cause to remember it. They could well believe he was capable of melting rocks if his anger was hot enough.

“Seriously…. Yes, I think it must have something to do with what happened.”

“Can’t be,” Chris said. “Have you noticed…. The closer we are to the mountains, the less radiation there is. It’s almost normal enough to take off the hazmat suits now.”

“Are you sure the monitors are working properly?” Davie asked. “Because that does not make sense. Any kind of radioactive accident – whether it's nuclear or granddad’s temper or whatever – ground zero is where the residual radiation is STRONGEST. Granted it's been a couple of centuries since it happened. That should mean that the edges of the affected area should be creeping back, shrinking. But it doesn’t START from the middle.”

“I know that,” Chris told his brother. “But look at it for yourself. This area is near normal. And… look…”

Chris bent and reached out his hazmat gloved hand to the small, scrubby plantlife that was growing in a rock crevice. It was the sort of plant that was the first to inhabit the wasteland in the aftermath of a volcano, that could draw whatever moisture there was out of the air and the ground around about, that could spread its roots in the very shallowest and poorest of topsoil and manage to live despite every reason not to live.

His fingers, encumbered by the thick protective gloves, bruised the small blue flowers – they had to be blue, of course - but he had a feeling they would quickly recover.

“We keep the hazmat suits on,” Davie insisted. “I know it's a pain, but for one, we don’t know what it's like inside the caves. For another, we have to go back through the affected area to reach the TARDIS.”

“No we don’t,” Chris reminded him. “The fast remote pilot works brilliantly. We can call the TARDIS to us when we’re ready to leave.”

“Yeah, but that would be cheating,” Davie said.

“By whose rules?” Chris pointed out. “We’re the Lords of Time – in training anyway. We make the rules.”

That wasn’t entirely true. The Lords of Time had a long list of rules – a framework they had to work within – infringement of which could cause cataclysms that could collapse the universe in on itself. Their great-grandfather had talked endlessly about the importance of obedience to those immutable Laws of Time.

And then broke almost all of them himself, of course.

HE had one overriding law. “Because I’m The Doctor and I say so.” But that law only applied to him. Everyone else had to be more careful.

Still, using the remote control on the TARDIS hardly qualified.

They reached the entrance to the main cave system. There, again, there were signs of great heat once having been present. The walls of the caves were fused like glass. Chris took off one of his gloves and touched it. There was about a half inch crust of that glassy substance.

“Are you NUTS?” Davie told him. “You’ve exposed yourself.”

“There is no danger,” he assured his brother. “There is NO radiation here.” He took off the hood of the hazmat suit and the gloves and put them in his backpack. Davie reluctantly did the same. But Chris was right. There was no radiation here.

But that made no sense whatsoever. Davie was right about ground zero. This all seemed back to front.

“Maybe the ordinary laws of physics don’t count on a planet with a blue sun?” he said.

But that made no sense, either. The blue sun was only a different sort of sun. It had a different chemical composition to the ones they were used to, but it worked by the same immutable laws of physics that they knew and understood.

The planet worked by those same laws more or less. It HAD been scarred when the envelope of physical possibility was pushed to the limit. They weren’t sure if what their grandfather did was a mistake, an accident for which he had certainly paid the price, or a deliberate action to prevent an evil thing from succeeding in some ghastly plan. But either way it had left its mark on the planet.

But something else had happened that was doing something very strange to the laws of physics. This cave system WAS the origin of what happened. They both knew that instinctively.

“Wow!” They both said it together as they emerged into a large cavern that clearly WAS the absolute ground zero itself of that cataclysm long ago. But that had made it even more beautiful than ever. Every surface - walls, ground, the high, cathedral like roof - had been turned to glass by the blast. They reflected the glow that emanated from the centre of the cavern where a column formed from stalagmites and stalactites rose to the ceiling. The column was covered with the blue crystals The Doctor had told them to look for. And they were the source of the glow. They looked almost alive.

Davie pointed the radiation detector at the crystal formation. The needle stayed at zero. He switched it to detect several different forms of radiation with different characteristics and it registered zero for all of them. In case it really WASN’T working he pointed it to his brother. It moved a few points, proving that Chris still carried within him some of the artron energy he had absorbed in Tara. The detector worked. The glowing crystals were not radioactive.

Chris reached out and touched one of the crystals. It broke off easily. It was the size of a pear, the shape of the great Koh-i-nor Diamond of the old British Empire, and a shade of blue like the Earth sky on a clear winter’s day. It didn’t glow once it was separated from the rest, but it did glitter like a precious jewel.

He pocketed it. “That’s mum’s birthday present sorted,” he said.

Davie reached out and took one as well. The crystals looked to him like a source of power. He figured there was SOME use a smart engineer could put them too.

“Well, that’s that. Do we go home now?”

He stopped talking. His face paled. He felt something. It felt like…

Not life. Not exactly.

But intelligence.

A mind.

“Look!” Chris turned around and around as the mirrored walls shimmered and shapes began to resolve themselves. It was like looking at a fuzzy TV picture that flashed and faded and came back.

“What is it?” Davie asked.

“It’s a memory. A memory of what happened here. The CAVERN… the walls are…. They’re remembering.”

“They’re what?” Davie looked at his brother. “How can they…”

“I don’t know. I think….” Chris had that look on his face that Davie recognised. It meant that he was listening to something on another level.

“This place WAS the ground zero when a radioactive reaction destroyed a creature with strong mental powers. Powers nearly as strong as Granddad himself had. The creature was killed, but somehow its mind was absorbed by the walls of the cavern. And it… it fed on the radiation. That’s why there is none here now. It used the radiation to survive. To gather strength. It’s been sucking it up from the surrounding area like somebody drinking milk with a straw. The cavern itself is a mind, with a memory, with thoughts and ideas.”

It was remembering now. The pictures seemed to be getting stronger and clearer, as if they were being tuned in and refined. The twins watched the memory of a great mental battle between two great minds. The creature that lived in the cave and a man – a silvery-haired man in late middle age by Earth standards, with a distinguished looking face and kind eyes. They knew who he was straight away.

“Granddad,” Davie said proudly. They knew that the thing he was fighting WAS evil, and he was prepared to fight it till death if he must, for the sake of others. Just as he always had.

They SAW the radioactive cataclysm. And they saw him overwhelmed by it as he ran from the cave. They FELT it. The pictures in the walls were formless now as they represented the immediate aftermath, but inside their own minds the pictures continued. They neither of them were sure how, but they seemed to be seeing the events that immediately followed through their great grandfather’s eyes. They felt his pain as the radiation enveloped him. They felt his fear.

Fear?

Yes, of course. They knew that he was not fearless. Far from it. He had taught them that fearlessness was a lie. Everyone feared. Everyone was afraid. The brave carried on despite their fears. Cowards were those who gave into it. He was a brave man, but he was afraid.

Afraid to die on this planet, far from everyone he loved. He wanted to reach home before this body died and his regeneration began. They felt that so strongly.

Home?

Gallifrey was his home. The planet he was born on. But the co-ordinate he set when he reached the TARDIS was not Gallifrey. Chris and Davie felt as if they had discovered something enormously significant, not only about their great-grandfather, but about life generally.

Home was not the planet he was born on. It was where the people he loved were.

“Who is she?” Davie asked as they saw in the vision a young woman with dark hair who caught him as he fell out of the TARDIS door somewhere back on Earth. She was beside him as he regenerated, crying softly, frightened by all she witnessed, hardly daring to hope that he was going to survive.

“No idea,” Chris said. “His girlfriend back then?” That didn’t quite seem to fit but there was no other explanation. In any case he wasn’t thinking of the woman. He was picking up very strongly now just how painful it was to die of radiation poisoning. He could feel what it was like to die, and once dead, instead of oblivion, peace and freedom from pain, to have the pain and suffering intensify as his body was rendered into its constituent molecules and reformed into a new shell for the mind and soul to occupy.

“How are we seeing this?” Davie asked. “Are we in connection with him still? Is he telling us this?”

“NO,” Chris said. “He was fighting the creature mentally. Some of his memories, his mental power, seemed to have been absorbed along with the creature’s mind. We… I suppose we picked it up strongly because of who we are. Because of OUR connection with him.”

“Doctor!” The voice echoed around the cavern. “Doctor… you return.”

“No…” Davie began. We’re not…”

“Yes, we are,” Chris told him. “If the creature is seeing our DNA…. Then we ARE. It knows us as HIM. Because our DNA is similar enough to his…”

“Talk with words,” Davie warned him. “Not with your mind. It doesn’t have EARS. But it can see into our minds.”

“What do you want?” Chris asked telepathically. “What do you want from me?”

“I want your mind, Doctor. Joined with mine. Your intelligence. The remnant of your mind that was fused with mine… even that remnant is so rich… with your whole mind joined with mine I shall be invincible.”

“What is the use of being invincible?” Chris asked. “When you’re trapped in a cavern. When you ARE the cavern.”

“Your mind is not trapped. You are free. The fused mind will occupy YOUR brain, your body. I will be free to go where I choose. With the superior intelligence of the fused mind we will conquer planets.”

“It’s BLOWN a fuse!” Davie said. “It’s MAD.”

“Granddad always had one thing to say about that sort of idea,” Chris told his brother.

“Not the old take over the universe plan!” They chorused. “Come on! Is that the best ambition you have?”

“The power will be mine.”

“Close your mind to me,” Chris yelled to his brother. “It’s focussing on ME. It thinks I’m him… Granddad. It’s trying to get into my mind. Don’t let it affect you as well.”

“What are you going to do?”

“I’m going to fight it,” he said. “But you have to stay safe. Keep your mind clear. I might need you….”

Chris groaned aloud as he felt the cavern mind try to get into his. He closed his consciousness to it, to every outside influence. He put up mental walls around himself as quickly as he could, blocking out the alien mind that wanted to use him for such evil purposes. It was like a computer game he and Davie used to play before their great-grandfather taught them how to play better games without need of a computer. The purpose of it was to build defences and defend a city from attack. Chris had usually chosen to be defender, building strong walls and maintaining them against the onslaught of Davie’s trebuchets and catapults and canons. He did that now. His mind was the city and he built strong walls around it and he maintained them. Everywhere there was a weak point the enemy might use he strengthened the wall. It was exhausting work, but he managed it.

How long for, he didn’t know. He didn’t know what his own limit was, only that he HAD limits. He knew he was not invincible. But he had to hold out as long as he could.

“Chris!” Davie yelled. “Chris… be careful.” He knew what his brother was doing. He could feel the mental walls as if they were physical things. They were shutting everything out. Even him.

That was frightening. They had shared each other’s thoughts for as long as he could remember. Longer, even. Chris wasn’t the only one whose dreams got a bit surreal at times. Try remembering before you were born for a strange experience. Being shut out of what he had always regarded as the other half of himself was frightening, lonely, and the longer it went on the less sure he was that Chris could bring the walls down again afterwards.

“Leave him alone,” Davie screamed out loud and mentally. “He’s NOT The Doctor. I AM!”

The cavern mind hesitated in its effort to penetrate Chris’s mental wall and Davie felt it look at him. But he was prepared. He didn’t put up walls. He put up mirrors. He reflected the mind back at itself.

And then he smashed them.

He felt the satisfying sound of glass breaking in his head, and all around the glasslike walls began to crack with a sound nearly as loud and satisfying. He could hear the mind cry out in rage and it tried to fight back. But as what passed for its synapses became fragmented and disconnected it became less coherent and random. It couldn’t find him. It was lost in itself, unconnected shards of memory trying to form on the broken walls. But they were just memories, and fading ones at that. The mind was dying.

Davie felt a little sorry about that. It WAS a pretty unique thing. A cave with a mind of its own.

But his brother was a unique lifeform and it had attacked him. He had to defend his brother. Davie turned to Chris and reached out to him both mentally and physically. Mentally, he was still blocked out. The mental walls were holding against any intrusion, even his.

Physically, Chris was only standing up because that was the last thing his body was doing before his mind retreated and left it to its own devices. When Davie touched him he collapsed as if every one of his muscles had forgotten its function. Davie caught him and held him and reached for his TARDIS key as he did so. He hoped the remote function would work in a place like this. If not it would be a very long walk carrying him.

“Tell you what, Chris,” he said as he felt the TARDIS materialise around him. “Next trip we go on, no caves. You always seem to get in trouble when we go in places like this.”

Chris didn’t respond. Davie laid him down on the floor and knelt beside him. He tried again to reach into his mind, but he couldn’t penetrate his defences.

“Chris!” Davie whispered to his brother. “Oh Chris, don’t die. I need you. Mum will kill me for not looking after you. Granddad.... He’ll be heartbroken.” He put his hands over his brother’s two hearts. At first he thought they had stopped altogether. As he mentally reached inside though, he could see that they WERE beating, but only very slowly.

He tried again to reach into Chris’s head, to find out what was happening in his mind, but the walls were too thick. And if he tried to force his way in he knew he would be resisted still further. He seemed unable to tell hostile intrusion from their symbiotic sharing of thoughts.

The relief troops for the siege. Davie remembered the game too. There were meant to be doors that could open to let the relief troops in, to end the game.

Chris had not left any doors.

“Chris,” he whispered, close to his brother’s ear. “I’m getting us home to granddad. He’ll know what to do.” He kissed his brother’s cheek and stood. He programmed his TARDIS with the co-ordinate that brought him to his grandfather’s basement.

Communicating for the first time with so many of the young Israelites, scattered so far apart, had been satisfying, but mentally exhausting. When he was done, The Doctor had put himself into a deep, slow meditative trance to recover himself. He was there now, knelt in the centre of the inlaid Seal of Rassilon design on the floor of his meditation room. His hearts and lungs and other organs were near still and his brain was only functioning very slowly. His mind and body were recharging themselves.

But he was aware of the change in the atmosphere around him when what they still called the Chinese TARDIS materialised next to his own one. He opened his eyes as the door of the cabinet it had disguised itself as flew open and Davie rushed out. The Doctor stood and caught the boy in his arms.

“Steady,” he said. “Calm yourself. Whatever it is, you have to be able to breathe first before you can tell me about it.” But in fact, he was picking up the gist of the problem anyway. Davie’s telepathic signals were so strong. “Show me.”

Davie still hadn’t managed to get a coherent word out, but he grasped his great-grandfather’s hand and pulled him into his TARDIS. He went straight to Chris’s side, examining him quickly for physical injuries before putting his hands either side of his head and reaching inside to feel his injured and closed off mind.

“What caused this?” The Doctor asked as Davie knelt anxiously next to him. He listened to the explanation and his hearts sank.

“He’s too young to take on something like that. He’s not even transcended.”

“Make him all right,” Davie begged. “Granddad… please make him all right.”

“I’m not sure I can,” The Doctor admitted with a catch in his voice. “His brain has shut down to protect itself. But I can’t find the activation switch.” It was worrying. He WAS physically ok for now. But his body NEEDED the connection with his brain. His heart needed to be told beat, his lungs to breathe.

“No!” Davie was close to tears. He hugged his brother in his arms. “Granddad… I thought you would know. I was sure you would….”

The Doctor felt his disappointment. In all the years he had known them this was the first time he had been unable to help one of them in trouble. He had let them down. That feeling was worse than the grief they both felt about Chris’s condition.

“The Cloister Room,” The Doctor said. “The energy there will stop him worsening while we find a way.” The Doctor made to lift him, but Davie stayed his hand. He lifted Chris into his own arms.

What was that song, The Doctor thought as he walked by his side. ‘He ain’t heavy, he’s my brother.’ It might have been written for these two boys with their deep love for each other.

Davie laid his brother on the floor by the side of the pagoda-shaped well cover that hid the fragment of the Eye of Harmony. He knew The Doctor was right. Here in the Cloister Room it was as if time itself was neutralised. Chris’s condition would not worsen. But he could get no better either.

“Who’s that?” Davie asked, suddenly feeling another presence in his mind. For one frightening moment he thought the cavern mind was still there. “Granddad…”

“It’s Sukie,” The Doctor said. “Your sister is calling you both.” He turned and ran out of the TARDIS and up the stairs. Sukie was in the nursery with Vicki. The two of them were kindred spirits nearly as much as the twins were. They were both older than their years and they both found it easier to hold their conversations telepathically. As he stepped into the room he smiled to see them both exercising their psychic powers to the full. The puppets in the rather elaborate toy theatre he had bought for Vicki’s third birthday were being manipulated by telekinesis to perform a ballet. Stravinsky’s Firebird, he noticed. He smiled as a long buried memory came back to him. It was his first wife’s favourite ballet.

“Children,” he whispered in words. They turned to him. The puppets gently folded upon themselves.

“We wanted Chris and Davie to come and see the puppets dance,” Sukie told him.

“They will later,” The Doctor promised. “But Chris is not feeling very well. Sukie, will you come and see your brother and maybe you can make him better?”

Sukie nodded and stood. Vicki ran to him and he picked her up in his arms. “Come on, my little love,” he said to her. “No need for you to fret on your own.” He brought both girls with him as they descended the stairs. Through the half open door he saw Rose sitting in the drawing room with Peter cradled in her arms as she talked with Susan. There was no need for either of them to be worried about this just yet. With luck they need never know.

Sukie went to her brother’s side as soon as she entered the Cloister Room. She knelt by him and put her hands on his face. Vicki indicated that she wanted to be put down from her father’s arms and he did so. She went to the other side of Chris’s still form and she, too, touched his face.

“Granddad,” Davie asked in alarm as he came to his side. “What are they doing?”

“They’ve both got way stronger telepathic powers than either of us,” The Doctor told his great-grandson. “If they can’t get through to him, then….” He didn’t want to think of the consequence. They HAD to do it. He hugged Davie around the shoulders and hoped.

They could both hear what the girls were doing. They found the secret door that Davie had sought in vain. Very slowly, they were opening the way into Chris’s mind. They were the relief troops, and they were ending the siege.

“He’s in there still. He’s ok,” Davie said with relief. “But can they bring him back to us?”

“Yes,” The Doctor assured him. He felt certain now that they could. He could feel the door widening. Chris’s mind did, indeed, feel whole. He had not been permanently harmed by the experience. But he did need help to find his way back to the world.

And the two girls were giving him that help. Their gentle minds were soothing the trauma he had suffered, making him feel safe now. Slowly the walls around his consciousness were crumbling away. At last they saw him open his eyes and look up. He saw Sukie and Vicki sitting over him and he smiled.

“Yes,” he said. “I would love to watch your puppet show.” He sat up and then stood. He swayed dizzily at first, then steadied himself. He hugged the two girls, then reached out his arms to his brother. The little girls looked at them both and knew they were not needed just now, and went back to The Doctor.

“I’m all right,” Chris said at last. He looked at his great-grandfather. “It thought I was you. That’s why it tried to take over my mind.”

“Chip off the old block,” The Doctor said with a smile. Then he sighed. “All my old enemies are your enemies now. Not the best legacy I could give either of you.”

“We’re ready for it,” Davie told him. “I know this went a BIT wrong. But we’re ready. Chris and me… and if we need them, Sukie and Vicki are there for us. Even if you weren’t, granddad, we’d all be ok.”

“Seems like it,” he admitted. “But I’m not going anywhere for a while.” He looked at them and smiled. “Your mum’s upstairs you know. If she gets wind of this you won’t be going anywhere either.”

“You’re not going to tell her…”

The Doctor smiled enigmatically. He carried Vicki and took Sukie’s hand as they left the TARDIS and came up to the drawing room.

“The girls would like us all to watch their puppet show,” The Doctor told Rose and Susan.

“We’ve got you a present, mum,” Chris added as they all went upstairs to the nursery. He reached in his pocket and pulled out the perfectly formed blue crystal. “Happy birthday.”

Susan took the crystal and looked at it and smiled. On the edge of her own telepathic senses she had a feeling there was a bigger story to how they got the crystal than they were ever likely to tell her. She knew better than to ask.