He closed the wing door and looked one more time at the two brothers, then he initialised the drive. The garden of Mount Lœng House in 3343 vanished and he was in the vortex again.

But something was wrong. His instrument panel was giving out insane readings, and the vortex was not the cool blue it should have been. It seemed to be every colour at once. He felt as if the Prototype was being dragged sideways as well as backwards in time.

Then it stopped. He looked around. It was the same garden of Mount Lœng House. But it was different enough for him to realise this wasn’t HIS Mount Lœng House. This wasn’t HIS universe.

The high steel fence with barbed wire that cut off the view of the river everyone in the family cherished was one thing. He recognised an anti-transmat barrier rising some 20 feet above it.

The guards were another.

Uniformed guards, with guns. Patrolling the grounds.

“Who’s that?” A shout went up and Davie turned to the sound of a pistol being cocked. “Oh, it’s YOU!” The pistol was lowered but the look on the guard’s face was hardly reassuring. “What have you done to your hair? You look like the other one. HE won’t like that.”

“Who won’t like it? What?” Davie asked. “Who are you and what’s going on?”

He saw a shadow behind the man in the half-light of dusk. He recognised the figure who crept silently behind him, but not for nothing had he learned the arts of the Shaolin. Not even an eyelash flickered as he watched his brother apply a pinch to the neck that rendered the guard unconscious. Chris knelt and whispered something in the man’s ear then he stood and looked at the Prototype and then at Davie.

“You…. It can’t be you. You must be…. You built your Prototype like you always wanted. It jumped tracks… you’re from an alternate universe…”

“Yes,” he said. “I think that’s what happened. Chris…”

“Help me get it into the stables. We’ll be in big trouble if any other guards see it. I made that one think he’s had a blackout. He’s going to wake up and sign off sick for the night.”

“Ok.”

“He’ll probably be fired for it,” Chris added. “But hell, there are better jobs even in this world than working for HIM.”

“Who’s him?” Davie asked as they pushed the Prototype into the stable where it was built. At least it was in his world. Here, he could tell, no such thing was ever done. The stable was still the disused, empty space it was when The Doctor gave it to him for a workshop.

“Chris, what’s wrong with this reality?” he asked. Chris didn’t answer. Not in words anyway. He wrapped his arms around his neck and held him tightly. Davie felt his brother’s kiss on his cheek and tears wetting his face.

“I am so glad to see you. I have missed you so much. I… hurt… grief… had to… wish I could die… wish he would kill me too.”

“I’m…” From the incoherent words between heavy, grief-laden sobs Davie grasped one fact. “I’m DEAD?”

“Yes,” Chris said, his head on Davie’s shoulder as he continued to hold him. “Two years. I’ve missed you so much. Think of you every day. Miss you. Even if this isn’t right, it's good to see you. To hold you. I love you, Davie.”

“I love you, Chris,” he told his brother. It WAS his brother. It WAS Chris. A Chris from an alternative universe, yes. But it WAS Chris. He could feel his psychic identity so strongly. The familiar feeling of their brotherly love, mixed with grief and fear and much more, was pouring from him. It was almost overwhelming.

“But what’s going on?” he asked. “Why am I dead? What happened?”

“HE killed you,” Chris answered.

“Who did?”

“HE DID,” Chris said again. “He…” Chris couldn’t talk any more. His emotional state was so intense. But images flashed into Davie’s mind. Chris, hiding as he witnessed a vicious, murderous confrontation; Davie trying to defend himself; a rope around his neck; eyes full of tears of pain and betrayal as the noose was fixed to the rafters of the very room they were stood in and he slowly strangled in pain and agony. His killer had stood there, watching, with murderous satisfaction on his face. Chris’s view of his brother’s eyes dimming as the life died in them was the last lingering and terrible image of them all.

“I was too scared to help you. He would have killed me too.”

“It can’t be true, Chris,” Davie cried. “It can’t be. He wouldn’t do that to either of us.”

“He DID,” Chris sobbed. “I saw it. I saw him kill you and then walk away, leaving your body hanging there. He put it about that you committed suicide. Everyone believed it.”

“Chris!” Davie still couldn’t take it in. “No. How could it be? Not…. Not Granddad. He wouldn’t.”

“Granddad?” The word made Chris sob even harder. “He hasn’t let me call him that for years. I have to call him SIR. He’s not…. I don’t… He’s NOT my granddad. He’s EVIL. He killed you. I think he killed our dad, too.”

“What?”

“And other people, too. Anyone he saw as a threat.”

“How different can this universe be?” Davie asked. “Chris… What happened here?” He looked around the stable. It was dark now, but with his Gallifreyan eyesight he could see much of the detail still. It seemed to be a rough living quarters. There was a bed and clothing hung up. food piled in a corner. Chris lit a very old fashioned oil lamp and opened a tin of corned beef. He made sandwiches and divided them between two mismatched plates.

“You live here?” he asked. “In the stable? In the place where I....”

“I’d rather live with your ghost than with HIM,” Chris said. “I only stayed here because somebody needs to look after Rose and the kids.”

“You’d better start from the beginning,” Davie said as he sat down and ate one of the sandwiches, not so much out of hunger as to give a semblance of normality to what was a thoroughly abnormal situation. “It can’t always have been wrong. He bought this house. Rose and him got married. It must have been right once. We WERE all happy.”

“It started…” Chris swallowed his food and sighed. “In your world everything is fine? It all worked out? You’re happy?”

“Yes,” he said. “But not here. Something is VERY wrong here.”

“We went to a planet where we found remnants of Gallifreyan society. People who had escaped the destruction?”

“Yes,” Davie said. “The Children of Israel, he called them.”

“Promised them mastery over Humans. Promised them they would be all powerful under him.”

“No.” Davie shook his head. “He promised them peace and freedom from fear. That’s all. All powerful? Mastery over Humans? That’s not Granddad. He doesn’t think like that.”

“He DOES now. I think it began right back before he and Rose were married. When he says Rassilon spoke to him and promised him Gallifrey would live again, that the Time Lords would succeed. He became DRIVEN. His whole ambition is to have Time Lords rule this planet. He pushed Christopher to reach the highest level in the government. He’s….”

“Well he did that in my world, too. Christopher is a really caring politician, looking after his constituency.”

“Not here. He used him to find ways of discrediting members of the government so that he could put his OWN people in. There have been fifty-four by-elections in Britain in three years and they have all been won by Gallifreyan settlers. I think he probably rigged the votes somehow. But he’s slowly replacing Humans in government with his own people.

“That’s all WRONG,” Davie said. “Granddad has been teaching them to be patient. He wants them to be a part of Human society alongside Humans.”

“No,” Chris said quietly. “Not here.”

“Christopher went along with this?”

“At first. Until he found out that HE had a friend of his murdered in order to force a by-election. He said he wouldn’t do it anymore. Then dad… None of us believed that he would hang himself. I never did. Mum didn’t. After the funeral Christopher stole his TARDIS and took Jackie and mum and Sukie away in it. I think they went back to the 21st century, where Jackie comes from. He wanted us to come, too. But we both said we’d stay and try to fight him somehow. Davie… MY Davie… destroyed our own TARDIS so HE couldn’t use it to follow them. But that meant we were trapped here in this time with him. When HE found out, he got in such a rage. He called Davie a traitor. He fought him. I am sorry. I should have tried to help. I watched him kill you.” Chris gulped for breath before he went on again. “Mum doesn’t even know. There was no way to tell her.”

“I’d rather she didn’t know,” Davie said. “That’s…. Oh Chris, I am so sorry. How can you bear to live like this though? It is so different to where I come from. We’re happy there.” He thought of Brenda. It looked as if here, in this reality, he never even met her. Perhaps she was dead. Her family and everyone in her neighbourhood only escaped the volcano because of the intervention of himself and Chris and The Doctor. They must have died.

And his father. What Chris had said about him was only just sinking in. No, his father wouldn’t commit suicide. He had lived through the Dalek invasion as a young man, brought up a family in the aftermath. He wouldn’t just kill himself. HE would have fought against this new threat to his world, even if it was his own wife’s blood that was responsible this time.

His own great-grandfather, the man he loved above all men, who he owed his entire being to, who had shaped his whole way of thinking, murdered his father.

Davie shook his head as he tried to accept that mind numbing reality.

“It can’t be,” he said again. “Even in an alternate reality, he’s still… still The Doctor, the man who saved this planet so many times. The one who CARES for the whole universe.”

“Not any more. He’s changed so much. I know it’s hard to believe. We used to love him as much as our own father. More, maybe, in some ways. He meant the world to us. And then…Then he changed. He became COLD. He became…” Chris swallowed hard. “He became a monster.”

“HOW?” Davie asked. He refused to believe it was possible that ambition changed him so much that he became a murderer of his own flesh and blood. “What did that to him?”

“He DID it to himself,” Chris insisted. And I… I HATE him. I wish I had your courage… I wish I could fight him. I wish I could KILL him.”

“Chris!” Davie reached out and held his brother. “Chris, that’s not YOU either. You are the most gentle soul in the universe. You… in my universe you’re a beautiful thinker with plans to enrich this world with your thoughts and ideas. You would NEVER…”

“In THIS universe he has destroyed us all,” Chris answered. “We never had a chance to be who we wanted to be. He didn’t even let us transcend. After all the effort, our hopes and dreams. He said… He said YOU were too powerful already and I… He said I was too much of a weakling. He said a dreamer like me didn’t have what it takes to be a Time Lord.”

“It ISN’T him. It can’t be. He wanted us to be Time Lords. It was HIS driving ambition. For us to be the future of our race.”

“It all changed,” Chris insisted. “HE changed, and he plans to change this whole planet. When I look into the future… all I see is darkness and fear.”

Davie shuddered. He knew Chris had stronger precognition than anyone. In his own world he had strong visions about the Sanctuary. He often sat with him in the evenings, looking at the work progressing, and he would talk about it. He would close his eyes and see people in the Sanctuary and tell him their names and their ambitions, and what their strengths and weaknesses were. They both looked forward to a future when they would meet those people who would be coming to learn Chris’s way of meditation, his gentle path to strength and wisdom.

“Look.” Chris took hold of his hand. He closed his eyes. Davie closed his and saw what Chris was seeing. A world of servile misery for Humanity, where people could be killed for the slightest hint of rebellion. He broke the connection. He didn’t want to see any more.

“Chris, tell me this is a dream. I lost consciousness in the vortex and this is just a horrible nightmare.”

“It’s real. But it’s not your reality. You can go back to your own world and forget it.”

“I’ll never forget this. It will haunt me forever. Even if I CAN get back, I don’t think I’ll ever be able to look him in the eye again. Knowing THIS. Knowing that such darkness IS in his nature, part of his soul.”

“No, Davie,” Chris said to him. “When you get back to your world where it’s all good and clean and wonderful… the world I feel in your head… you must forget us.”

“I can’t get back yet, even if I wanted to,” Davie replied. “I think I need to recalibrate the vortex drive. But I can’t do that in this light. I’m stuck in this world tonight.”

“At least I have your company for one night then,” Chris said. “I’ll go up to the main house later and get some better food. I usually go and see Rose for a bit in the evening.”

“He isn’t here?”

“Not just now. He comes home from time to time. He never announces his arrival. He just turns up. She waits for him. Poor Rose. She loves him, still. Even though she’s scared of him. She won’t hear a word said against him. Even though she knows the things he’s done. She cries a lot. She wants him back, the way it was. But she won’t stop loving him even so.”

“She has children by him?”

“Four so far. Vicki, Peter, and the twins. He won’t acknowledge them. They’re hybrids, like Sukie. He wouldn’t even give them names. He just calls them “the boy” and “the girl”. She’s having another baby now. And she’s afraid what he will do if that’s a hybrid, too.”

“Oh, poor thing.” Davie sighed. “Is there any happiness in this place?”

“Not much,” Chris admitted.

He went up to the big house later. Davie stayed hidden in the stable. He lay on the makeshift bed and thought about his real home and how very different this world was, and tried to work out how it could be that way.

He knew his great grandfather was a complicated man, a man with many different drives and ambitions, with a lot of sorrow in his hearts, a lot of bitterness. But never such darkness and hatred as this. Or if there was, he kept it buried deep in himself.

DID the man he knew in his own reality have such a cruel nature deep down? Could something trigger such a change in him, too?

He refused to believe it. His great-grandfather, The Doctor, a murderer, a cold blooded murderer? No. He would NEVER believe it.

How did it work? Alternate universes? How was it that the same people in different realities behaved in different ways? He always assumed that they were more or less the same people but reacting to different fortunes and different experiences with the same gifts they had in every reality. But it wasn’t the case at all. The Doctor in this reality was a cruel fiend. Rose in his reality was a feisty woman who was quite capable of bullying her husband if she felt he needed setting straight on some matter. In this reality she seemed to be a scared, battered wife, clinging to a memory of when he USED to love her, having his babies one after the other and hoping the man she married was in there still.

Even Chris was different. Of course he was always a sensitive soul. But here, he was so beaten, so hopeless.

He heard Chris whisper loudly as he slipped back inside the stable.

“I got some fruit and fresh cheese and ham,” he said. “Here…”

Davie took his share of the food and they ate in near silence. He didn’t know what else to talk about. He wasn’t sure he wanted to hear any more about this world and it would be too cruel to tell Chris about HIS world.

“Please,” Chris said. “Tell me. It would make me feel a little better to know there IS another world where it isn’t like this.”

“No, it wouldn’t,” Davie assured him. “It would just make it worse for you. Really it would.”

“Please,” he said again. “Davie, tell me about the Sanctuary. I saw it in your mind. It sounds wonderful.”

“It is. It’s your idea, Chris. You dreamt the dream and you’re going to make it come true.”

“I don’t think I have the will to make anything happen here,” he sighed. “The courage I had… I lost it when I lost you.”

“You handled that guard fine.”

“I did that for you. I thought I was dreaming. I thought you were a ghost. But you’re still my brother.”

“And you’re still MY brother,” Davie said. “So what can I do to help?”

“Nothing. Fix the prototype tomorrow and then go home. Have the life you’re supposed to have. And never take it for granted.”

“That isn’t enough. I have to do something.”

“Stay with me here until morning,” Chris said. “Remember when we were kids, when we were scared of thunderstorms. When we had bunk beds, and in the morning mum would find us both in the bottom bunk, cuddled up together. I was never afraid when we were together.”

“Chris,” Davie said. “You’re still a total girl even in this dimension.” Chris laughed and sobbed at the same time.

“You always called me that,” he said.

“Well, you ARE,” Davie told him. “But I don’t care. You’re still Chris.”

He wasn’t, of course. His brother was safe in their own reality. But this WAS another Chris.

A sadder Chris, with little to hope for in his life.

He could give him one night. There wasn’t a lot of options anyway. Unless he slept in the Prototype.

So as the night darkened, Chris blew out the lamp and the two of them lay together in the narrow bed. Davie remembered well enough the times when they were children and they would turn to each other for comfort when they had reason to be frightened.

There was reason enough to be frightened now and they turned to each other as they had always done.

They both woke early the next morning. Chris lay for as long as he dared, snuggled close to his brother, trying to pretend that this was the real life and the nightmare of his life WAS just a nightmare.

“We should try to get the Prototype fixed before anyone else is around,” Davie said eventually. “It’s light enough to see properly now.”

“Yeah,” Chris sighed.

“Chris,” Davie said when he had recalibrated the systems and plotted his course back through the vortex. “Why don’t you come away with me? Come back to my world.”

“I can’t,” he said. “I don’t belong there. I’m not even sure I COULD belong there. There’s another of me there. Doesn’t the Blinovitch Limitation Effect come into force?”

“Probably. But I could sort something out. You could live somewhere else. I could visit you.”

“What about Rose? I can’t just leave her. I have to look after her. One of these days he’ll kill her.”

“Chris…”

“What the bloody hell is going on in here?”

They both jumped, Chris more so, as a voice they both knew well echoed around the stable. Davie stepped out of the Prototype and looked at the man he knew as his great-grandfather.

It WAS him. The face, the eyes, the long, slightly hooked nose, the jawline were the same. But all seemed twisted into a hard, cruel expression that shocked him to the core.

He looked at Davie and for a moment he looked scared. Then he recovered himself.

“You… I killed you once. I’ll kill you again. And your useless brother. Time I was rid of you BOTH.” Chris screamed as The Doctor pulled a long dagger from inside his coat and lunged towards Davie.

He moved quick, grabbing a long screwdriver from the tools they had used to get into the Prototype’s systems. He held it like a knife and faced up to him. The Doctor slashed at him with the dagger, ripping his jacket and grazing his arm. Davie came back fast and the screwdriver stabbed into The Doctor’s shoulder. He stepped back, pulling it out and defended himself from a murderous counter-thrust.

“I’m going to KILL you again,” The Doctor said. “This time no mistake. You’re dead…”

“Granddad,” Davie screamed. “Stop it. This ISN’T you. I don’t know what happened to you. But this is wrong. You’re not like this. You’re not… I can’t believe you want to hurt me.”

“You’re a dangerous troublemaker,” he replied. “I can’t trust you. I don’t NEED you.” He slashed at him again and Davie’s arm bled as the dagger sank in. He dropped the screwdriver as his hand muscles jerked in response. He saw a satisfied smirk on The Doctor’s face as he raised his arm to stab again. Then he gave a soft, surprised cry and his eyes seemed to dim. Davie saw Chris’s shocked face as he pulled the screwdriver out of the back of The Doctor’s head.

“You killed him!” Davie was shocked, though not as much as Chris was. He grasped The Doctor’s body and laid him down on the ground. He knelt beside him. His face, seemed softer, almost as it should look. Davie reached to close his eyes.

“What the hell is THAT?” He shuddered as blood poured from The Doctor’s nose and with it some kind of creatures, like metallic bugs. Davie pulled his sonic screwdriver from his pocket and aimed it at the things. There was a crackle and a smell like fused plugs and the creatures stopped moving.

“It’s a…” Chris stared as Davie picked up one of the dead bugs with a sheet of paper. He looked at it closely.

“It’s a cybermat,” Davie said. “Miniaturised cybermat.”

“A what?”

“Cybermats… Cybermen use them as infiltration… Granddad taught us about them. Showed us pictures.”

“Davie… does this mean…”

“Just after he asked Rose to marry him, he had a run in with the Cybermen. He told me about it. I think… He must have been infected by them. In his brain.”

“He’s had those things in his head all this time?” Chris knelt by his side, too. He stroked his forehead. “Granddad, it wasn’t you at all. It was those things.” He looked at his brother. “Were they controlling him, or was it some side effect of them being in his brain – causing the personality change?”

“I don’t know. Either way… it WASN’T his fault. I knew he couldn’t be… I knew…”

“That’s a small consolation,” Chris noted mournfully. “He still had you and my father killed, and everyone else is gone. The country is in a mess…. And Rose…. When she finds out that I… I killed him…”

“Chris,” Davie said. “I’m going to sort this. I’m going to make it right. I’m going to make it ALL right. This world can’t be like it is.” He pulled Chris into his arms and hugged him tightly. “If I get this right you won’t know anything. I won’t have been here. But your Davie will be alive still.”

“What are you going to do?” he asked.

“Trust me.”

“Always.”

Davie got into the Prototype. He set the temporal co-ordinate and looked at his brother, still standing there. He opened the door again.

“Chris… get in. Come with me.” Chris looked at him and looked down at the body of his great-grandfather. He stepped towards the passenger door.

“Buckle up,” Davie said. “I don’t know how smooth this ride might be.”

He initialised the drive. The Prototype dematerialised.

They rematerialised in the same place five years earlier. The Doctor had only just bought the house. He and Rose had been living in the TARDIS in the basement while they bought furniture and put up curtains and planned their wedding. Chris and Davie slipped into the quiet house through the kitchen door and made their way down to the basement. They reached it just as the TARDIS materialised.

“Who the hell…” The Doctor was the first to step out, holding Rose around the shoulders. Jackie followed, and Christopher. “Chris… Davie… But…”

“I don’t have time to explain,” Davie said. “You guessed right. We’re from a few years into the future. And don’t give me the lecture about crossing timelines and interacting with past and future selves. The teenage versions of us are at school right now, pretending to be studying for O Levels they aren’t even interested in. Blinovitch isn’t a problem. You are.”

“Me?”

“Granddad….” Chris said. “Let Davie…”

Davie adjusted his sonic screwdriver and pointed it at The Doctor’s forehead. He blinked and put his hand to his nose as it began to bleed profusely. He took his hand away and gave a startled cry as he saw the dead cyberbugs among the blood and mucus in his palm.

“What the hell are those?” Rose demanded.

“They….” The Doctor looked at Davie. “They would have destroyed me if you hadn’t… How did you know?”

“If I told you I’d get one of your long lectures about messing with the Laws of Time,” he answered. “I’ve broken about four of them… not the ones about the Grandfather paradox or fiddling the lottery, but I’ve crossed a couple of timelines and I’m not even actually in my own reality. But I had to do it or nothing would be right.”

“We already had that argument with him tonight,” Rose said. “Davie… Chris… If you’ve done what you came to do…”

“We have,” Chris said. “I remember… everything is all right now. Rose… you and him are going to have a fantastic life. Your children are going to be beautiful.” He kissed her on the cheek and hugged The Doctor then he grabbed Davie by the arm and pulled him away up the stairs and out through the kitchen again.

“You did it,” he told him as they got back in the Prototype. “I can feel it. My memories are changing. Davie… you’re not dead. Nobody is. Everything’s ok.”

And he was right. When his equivalent of the fast return switch brought them back to when they left, the house and gardens were more like they were in Davie’s world. No fences, no guards, no oppressive, scared feeling.

“How do I know this isn’t my world?” Davie wondered as they stepped out of the stable and looked around.

“Because he shouldn’t be in YOUR world,” Chris said as he watched his brother walking up the path, with Sukie, Vicki and a pair of dwarf bears. “The bad stuff… the memory is fading. The horror of it… it all seems just a dream. I think soon it won’t even be that.”

“Go and give him a hug. Don’t tell him why. Just do it,” Chris ran and did just that. He looked around once, but there was nobody there. A gust of wind from inside the stables went unnoticed by anyone else.

Davie had another job to do. He set the co-ordinates once again, this time taking into account that he had to get back to his own universe. It was a bumpy ride. He felt nauseous as he came out of the vortex into the empty stable again. He pushed down the feeling as he jumped out of the Prototype and went into the house. He reached the basement just as the TARDIS materialised and was waiting when The Doctor and Rose emerged, followed by Jackie and Christopher. He did what he had to do with an inevitable feeling of déjà vu about it.

He knew he had risked a paradox. But when he went back and changed the future for Chris and for everyone else in the alternative universe he realised there was only one reason why the same horror hadn’t happened in HIS reality. Because HE knew what to do to stop it happening.

He sighed with deep relief when the Prototype finally arrived back just before tea time on the day he took it out for its first test drive. It seemed a long time ago.

He was very glad to be home.

“Davie!” Chris gave a cry of joy and ran towards him. “I knew you’d do it. You said you’d be home in time for tea. Great timing.”

“Fantastic,” The Doctor said as he, too, approached. “Davie… one thing… How DID you know about the cybermats?”

Chris looked at his great-grandfather with a puzzled expression as The Doctor knew he would. Davie blushed deeply.

“If I told you, you’d get mad at me, and I don’t want that to happen.”

“If they’d got a hold on my head…They would have burrowed into my brain and taken me over to their own ends. Probably some evil that would sicken me if I was allowed to be aware of it.”

“I know. That’s why I had to… But it’s ok now. It’s ok everywhere.”

“Davie…” The Doctor touched his face gently. Davie put up the strongest mental barrier he could. There were some things he COULDN’T tell him.

“You’ve had a traumatic time,” The Doctor said. “You feel… DIFFERENT. Something changed you inside.”

“I’m still me, granddad. Still me. I’m not changed THAT much.”

The Doctor wasn’t so sure. When he looked inside Davie he saw something that was more like himself.

“I think you’ve fulfilled some of that great destiny you were always going to have.” The Doctor smiled at him. “Davie, take it from me, great destinies are all very well. But don’t forget to be you as well.”

“I won’t,” he said. “But… Chris, are mum and dad still up here? I want to talk to them. I feel like I haven’t seen either of them for so long. I just want to…”

“And you call ME a girl,” Chris laughed as Davie ran to find his parents. He turned back and looked at The Doctor. “What happened to him? He wouldn’t let me see.”

“He wouldn’t let me see, either,” The Doctor answered. “He’ll probably tell you in his own time. Just be what you’ve always been to him. The other half of his soul.”

“I will,” Chris promised.