Author's Notes: This fic was inspired by a cleverly-done YouTube video about Nine and Eleven battling a "Time Lord Victorious" Ten: "Ten vs. Nine and Eleven" by AceTrax700. I've used the premise of this video as the basis for my fic and developed it from there. I have been unable to contact AceTrax700; however, the video has inspired and has been inspired by other fanworks, so I am merely the latest person to join in the creative community for this topic!

Disclaimer: This story takes place within the Doctor Who universe. This story is a way of re-interpreting concepts and ideas already present in Doctor Who. All characters belong to the BBC. This story is for fun and for sharing, but not for profit.

Warning: Major character death

Schrodinger's Doctor

The anomaly, the wrongness, spread through time and crept into their minds simultaneously.

The Ninth Doctor dropped Rose off at her mother's home in London for this was no adventure to run toward with a cherished companion. He left Earth with a sense of relief and immediately began searching among time and space for the cause.

The Eleventh Doctor hesitated, for he was supposed to be dead, and it simply wouldn't do to go haring off across the universe to embroil himself in entanglements as he used to do. But the wrongness grated across his innate sense of time and he found he could not ignore the clarion call.

They searched, each of them, for what seemed an eternity. Even for a Time Lord, this exaggerated description was right, for the fabric of Time itself felt warped and strained, and the two Doctors felt the dissonance skitter across their senses, almost like a howl at the edges of their perception.

Nine found the epicentre first, and at the heart of it hummed a very familiar and alarming signature. He materialized his Tardis nearby and barrelled out of the doors. The first thing he saw was a desolate beach, but he paid it no mind. Instead, he stopped in shock, for there stood another Tardis. It was visually identical to his own down to the blue of the paint and the patterns of the grain. However, the wrongness emanated from the ship in waves.

Behind him, the familiar wheeze sounded and a third Tardis pulsed into view. Eleven had arrived. For all that it took him longer to search, he came only moments later, for travel through time cancelled the difference. Like Nine, he exited and stared at the anomalous Tardis.

Nine and Eleven eyed each other warily. Nine sensed the little-felt but nonetheless familiar unease when in near proximity to another incarnation, and Eleven remembered who he used to be.

'This is why we can be here at the same time,' said Eleven. He licked his fingers and held them up in the air as if testing for wind direction. 'Oho! Something is very wrong on that Tardis.'

Eleven looked about him and Nine could see that he recognized this place. Something personal and perhaps momentous had happened here judging by the set of his face. 'Why here of all places?' Eleven mused, and Nine's suspicion was confirmed.

'Suppose we knock on the door and find out,' said Nine. He crossed his arms and narrowed his eyes as he examined the outer shell, searching for any possible explanation.

They marched up to the door. Eleven straightened his bow tie, harrumphed, and knocked three times.

The door was wrenched open and a wild-eyed Time Lord stood there breathless. But when he saw Nine and Eleven, he shook his head violently and he ran his hand through his hair.

'Nope. Wrong time. Wrong people. Sorry there, fellas!'

With that, he whirled on the spot and would have disappeared inside the ship. However, Nine grabbed his arm and hauled him outside. The unease of being near another of his incarnations increased.

'Do you mind telling me what you're doing?' Nine growled. 'Your ship is wrong, and you know it.'

Ten (for it was he) triumphantly opened the door wide. 'Take a look. Sorry, but you can't go in. She'll stop you if you do.'

Light pulsed red and the console, or what was left of it, stood swathed in a column of gleaming metal mesh. Cables and devices ran together within the structure in a hellish combination.

'What have you done?' cried Nine.

But Eleven was wide-eyed for he had caught enough of a glimpse to know exactly what it was.

'You've built a paradox machine,' he said. He waggled his finger at it, at Ten, and then for good measure, at Nine. He swayed on his feet. 'That's a paradox machine. I've felt those emanations before.'

'Molto bene.' Ten smiled smugly. 'And vastly improved on the original, if I do say so myself.'

'Why?' ground out Nine. 'What could possibly make you do such a hare-brained thing?'

Ten's smile disappeared and he stared at Nine, his eyes dark and wide. 'Rose. You are going to lose her in... from the looks of your time line... oh, I'd say a little over a year, maybe? And then you'll get her back and then lose her again, which will be your fault actually-as it was mine. This paradox machine will get her back. You'll be happy, believe me.'

'At the cost of the universe?' asked Eleven incredulously. 'I know exactly what you're trying to do. You can't break a fixed moment in time. You can't do this. I won't let you.'

'Tough.' Ten's lips set into a firm line. As quick as lightning, he shot inside and slammed the door. The Tardis began to wheeze and fade.

'Fixed moment in time?' asked Nine as they ran without thought together towards Eleven's Tardis.

'Yeah,' said Eleven. 'And I know exactly when he is in his own time-line. I don't know how, because I don't remember this, but he's gone mad. Time Lord Victorious. I remember that part of my time-line too well for my liking.'

'"Time Lord Victorious"?' Nine rolled his eyes as he fell into an immediately comfortable dance around the unfamiliar console, switching levers and twirling knobs. 'Fantastic.'

Eleven's Tardis shot off in pursuit.

~ o ~ O ~ o ~

The battle raged across the stars.

To escape Nine and Eleven, Ten hid the Tardis one second out of time. But Eleven knew this trick, having seen the Daleks do that in the Medusa Cascade. He had used it himself against the Master. Nine nodded appreciatively.

They ran him to ground on Ceelis III. All three hurtled through the alien jungle on foot, Ten always ahead, nimble and fleet. But Nine and Eleven doggedly pursued him. But when they had Ten backed against a sheer cliff, he activated a teleport and disappeared in a blue beam of light.

'Since when does the Tardis have a teleport?' Nine exclaimed when they found Ten's ship missing from where Eleven had trapped it in a stasis ring. Eleven only shrugged.

However, unknown to Ten, his Tardis now carried with it a small object fixed to the outside.

When Nine and Eleven rammed Eleven's Tardis against Ten's, and the two ships locked together screaming in protest, they thought they had him at last. But the ships hurtled through space and almost into the event horizon of a black hole. Ten ricocheted the linked Tardises off space matter that had not yet been irrevocably pulled into the gravity well. His ship wrenched away from the other from the stress of impact, coral supports groaning and debris raining down. He disappeared into the Time Vortex.

They chased Ten in the Vortex and caught up only because of a temporal locator Nine had attached to the outside of Ten's Tardis when they had originally trapped it within the stasis field. Fortunately, the Tardis had already been altered so much by the Paradox Machine, she either did not notice or care that one more device encroaching on her freedom had been attached. She did not alert her Time Lord. The Time Vortex howled around them, and the Tardises shook from the proximity within the time stream.

'Last chance,' Eleven shouted and he and Nine ran around the console, keeping their shuddering Tardis under control. The two ships hurtled through time much too close. Alone in his Tardis, Ten did not have the extra pair of hands, and so, when Nine and Eleven crashed their Tardis into his, he could do nothing to stop it. Flung onto the floor, he could only hang onto the railing post as his Tardis was flung out of the Vortex with a shriek of strained systems and the wrongness of it all.

Nine reversed the signal of the temporal locator to transmit. Eleven danced around the console and chose a destination. Both Tardises materialized with a crash onto a sparsely populated planet, in the snow, roughly half a kilometre from each other. Eleven and Nine ran headlong towards Ten's Tardis which was steaming slightly and singed around the edges.

Systems damaged and disoriented from the wrenching trip through the Vortex, the Tardis did not stop Nine and Eleven from forcing their way in.

The Console Room was a mess, though the paradox machine was intact. Chunks of coral littered the floor and Ten lay unconscious in a sprawl of limbs on the grating.

Eleven stared up at the gleaming wire mesh surrounding the console. 'Oh, Doctor, what have you done,' he murmured. He hovered his hand next to the mesh, but a spark jumped out and he jumped back, shaking his hand wildly. He spun around on the spot rapidly scanning the Console Room. 'She doesn't recognize me,' he said, wide-eyed. 'He's programmed her to not recognize me. How did he do that? Even the Master didn't...'

Nine scowled. 'Spoilers. He's mucked about with the Rassilon Imprimature and altered the Briode Nebuliser. Won't recognize me either.' He too reached out and was rewarded with a shock. 'That's that. He's the only one who can stop it.' He crossed over to Ten and knelt by him. He looked at him for a long moment. 'This is my future.' He shook his head and picked Ten up.

They took him to the Sickbay. Nine laid him on the diagnostic bed and they strapped him securely down. Taking no chances, they added unbreakable chains to his wrists and feet. They did, however, decide to allow him to stay un-gagged only after they had determined that he had not somehow rigged a voice recognition device. Eleven did not think he had met Idris but said nothing to Nine.

When Ten awoke, he came to with a start and struggled against his bonds, screaming in anger. But when he realized where he was and that Nine and Eleven were looking down at him, he calmed himself though he still breathed heavily.

'You've got me. Well done,' he said. 'But there's nothing you can do about the paradox machine. I will get Rose back. You'll never stop me!'

'We know,' said Eleven. 'I remember how single-minded I was when I was you. Don't think for one moment that's going to get you far. Not for one single moment. I won't let you, you hear?'

'Doesn't matter. Even now it is calculating the best moment for Rose to be taken out of her time line,' Ten gloated. 'The Tardis can still pilot herself there even without me, and Rose will have her key. She'll find her way in. Best not stop her! You'd pollute the time stream even further with your interference. Don't worry. I won't disrupt the time lines-any more than necessary, that is.'

'How considerate,' said Nine sourly. 'As if it would matter!'

'Yes,' said Eleven. 'There's not much we could do to the universe after you've scrambled it!'

~ o ~ O ~ o ~

So they left him strapped to the bed. As futile as the attempt might have been, Nine himself went back in Eleven's Tardis to find his own ship, and he retrieved Rose at the end of a visit with Jackie.

'I can't explain it to you,' Nine said to Rose. 'You would never understand it. Think of it as a temporal sickness. He thinks he is me. Humour him. No matter what he says, no matter how crazy it seems, humour him. Play along. You won't be able to undo the restraints and you can tell him that.'

'Act your heart out, er... as they say,' said Eleven. 'I know you can do this.' He looked at her wistfully but then turned away almost hastily, hands in pockets and attempted to whistle a jaunty tune.

Rose looked at the strange man oddly. Nevertheless, she called him "Eleven" as she was asked to do, wondering what his real name was, and she made her way to the Sickbay on the future Tardis that glowed red and had a butchered console.

The madman was asleep, or at least his eyes were closed when she came to his side. The bonds seemed cruelly tight and the chains grim. It struck her that the Doctor and Eleven must have been afraid of this man to have restrained him so tightly and carefully. She wondered who he was. For a moment she looked at his profile, the shock of hair jutting out and over his forehead, the sweep of his long eyebrows, the gentle, outward curve of his narrow nose, the firm line of his lower lip. It was an compelling visage and she found herself wanting to know more about him.

But when he woke, his outpouring of joy washed over her and she saw tears in his eyes.

'Oh, my Rose,' he said and she was confused. How could he know her? But his voice was soft and kind, and his large, brown eyes so expressive that she felt sorry for him. He didn't seem mad to her, although he acted as if he knew her well.

She called him Doctor and tried to undo his restraints, half acting and half sincere. He accepted that she couldn't and consoled her, saying that "they" had ensured that she couldn't. Nevertheless, he told her to find his sonic screwdriver.

She stalled, mindful of Nine's warning, by asking this "Doctor" how this happened and who Eleven was. His story was that Eleven was an evil being who had corrupted his past self (for of course she would recognize Nine) and that they were trying to stop him reuniting with her. It was a true enough story, from his perspective, and she could see he believed it. She wondered a bit at the phrase "past self" but let it go. He was mad, after all.

He looked so hopefully at her and with such longing that she touched his cheek with her fingers. He whimpered and she pitied him. She couldn't turn her back on such desperate yearning and so she stroked his hair. He leaned his head into her fingers like a cat, tangling his already rather wild, sticking-up hair.

'I missed you,' he whispered. 'I couldn't bear not being with you.'

'I'm here now,' she soothed, still stroking his hair. It felt right, somehow.

'When are you?' he asked.

'Sorry?' She was confused.

'When are you?' he repeated. 'When was the last time we saw each other? I need to know when in your time line you are.'

Her hand stilled. 'I was visiting my mum.'

'All right,' he said with just a hint of impatience. 'But before that. What was the last thing we did together?'

She withdrew her hand. 'I, um, we were on Earth.'

'When?'

'Uh...' She cast around for something. 'World War Two. With the gas masks.'

He paled. 'And before that we... we saw your father when he... he...'

Rose winced but then nodded. 'Yeah. That was it.'

Shocked, he looked at her up and down as if examining her. 'I can't feel the timeline, but that's the paradox machine.' He perused her further. 'Long hair. Permed.' His eyes widened even further. 'When you last saw me, how did I look? Like this or like him-the one in the leather jacket?'

Rose stared at him perplexed but then shook her head to clear it. 'Like you,' she said at last.

He looked relieved but wary. 'How did I fight off the Sycorax?'

'The... the what?'

He turned his face away and she saw tears on his cheeks. 'What's wrong,' she asked, almost begging. Even though he was tightly bound, she could still see he had gone limp.

'You don't know me,' he said, his voice low and rough. 'Be honest. You don't know me at all.'

She couldn't be dishonest with him although she felt she failed in her mission. 'Sorry, mate. I know you're not the Doctor.'

He closed his eyes tightly and his jaw clenched. She stroked his hair once more and it seemed to comfort him in some small way, though he was still crying silently. She whispered in his ear. 'I'm sorry. I don't know why you're like this, but he can help you. The Doctor can help anyone.'

He nodded fitfully and with that she stole away, thinking it best not to distress the poor man further.

~ o ~ O ~ o ~

She reported her failure to her Doctor and to Eleven who were waiting by the console and attempting to circumvent the paradox machine. Like her, however, they had had no luck.

Nine looked at her warmly and thanked her sincerely. But she was having none of that.

'What's going on, Doctor? And don't tell me I won't understand.'

Nine looked at Eleven and Rose saw some kind of understanding pass between them. Nine turned back to her.

'Remember the day your father died?'

'Of course I do,' Rose shot back, nettled. 'Wait, are you saying I changed history or something?'

'No, no,' said Eleven. 'Nothing like that. What the Doctor here means is-the consequences of what's happening here are on the same... same level.'

'He is trying to change a fixed point in time,' Nine said. 'You can't do that. Not ever.'

'Because it would bring the Reapers,' said Rose.

'That,' agreed Eleven, 'or worse. The unravelling of history, possibly of time itself. I should know.'

'Oh, really?' Nine gazed at Eleven, brows knit together. 'When was that?'

'Spoilers,' said Eleven.

'What's he trying to change?' asked Rose.

'If we tell you, we will have to erase your memories after.' Eleven stepped back and crossed his arms.

Nine took Rose's hand. 'I don't want to do that. Not to you.'

'Go on, then,' said Rose. 'Give it a go. I want to know. Do what you have to do. Just tell me.'

'It will be hard for you to hear,' warned Eleven.

'Rose,' said Nine, and he took her other hand and held both tightly. 'The man in the sickbay is a future version of me. So is he.' He looked up towards Eleven. Then he gazed back at her. 'Time Lords can change when they're going to die. Regenerate. It's a way of saving ourselves and staying alive. Only, we change.'

Rose's eyes widened and she stared at him. She gulped. 'Yeah,' she said at last. 'You really are an alien, aren't you.'

Eleven flourished his hands outwards, palms up to the ceiling. 'Guilty as charged.' He grinned goofily.

Rose frowned at him and then looked back at Nine. 'But,' and she shook her head as if to clear it. 'That means...' She pointed at Eleven. 'You're him, and the bloke in the Sickbay is you...'

'Yeah,' said Nine. 'The paradox machine, that thing around the console, is the only thing allowing all of us being here at the same time.'

'But... but... that means you know me!' Rose whispered. She looked at Eleven suspiciously.

'I'm sorry,' said Eleven. 'But you're right. I know all about you. Every last thing.'

Nine tightened his hands around hers and Rose shrank a little closer to him. And then, in the midst of her turmoil, she remembered.

'He loved me,' she said. 'And when he found out I didn't know him... He was so hurt.'

Nine winced. 'Part of being a Time Lord,' he muttered. 'Even a crazy one.'

'I've got to tell him I understand,' said Rose and she pulled her hands free from Nine's. 'Let me go. Maybe he'll feel better if he knows I understand about him.'

'Rose,' said Eleven, 'thing is, you are the fixed point he's trying to break.' He clasped her shoulders and stooped so he was at her eye level. 'He is trying to get you back. He lost you and is trying to get you back from an earlier point in your time-line. But if he does so, he will alter a fixed point later on.'

'Later on?' asked Rose. 'So I'm not dead? That's not how he... you... he lost me?'

'I don't know,' said Nine. 'Only Ten and Eleven know. It's in my future, so I can't know. There's no erasing my memories.'

'You're still alive,' assured Eleven. He let go of Rose and spun around on one foot. He raised his voice. 'Very alive and quite all right. Enjoying life out-' He waved carelessly behind him. '-out there. But I won't tell you anything else. He, Ten, that is, won't tell you either, if any shred of training is still left in him. No use trying to ask.'

'But if you're the most future him,' Rose said, 'then you know everything. You remember everything that... that he-Ten?-tried to do. You already know how you stopped him... or yourself. Or something.'

'That would be simple, yeah,' said Eleven. 'Problem is, he is a different version. Existing in the same universe, but not exactly part of my time line. Nine, that's your Doctor, yes. But Ten is something else. He is a full Time Lord-exactly as I am. I remember being him, but I don't remember any of this.' He gestured at the paradox machine and shook his head.

'Will I...' Rose hesitated. 'Will I love you-him-you in the future?'

But Eleven turned away at that question and Nine looked uncertainly back and forth between the two.

'Some things are better not knowing until you know them,' Eleven muttered and he looked down at his shoes. 'If there's something to know.'

~ o ~ O ~ o ~

At Rose's insistence, they returned to the sickbay, but not before Eleven made Rose promise to keep up part of the charade.

'You were brought back by the Tardis,' he told her. 'At a time calculated to work best with preserving time-lines. If he believes that...'

Nine snorted. 'Not likely to give up. He won't.'

'I know. Worth a chance, though. Wouldn't you say?'

Nine shrugged and they entered the sickbay.

'We told her what you did,' said Nine without preamble.

Ten opened his eyes, but they were dull. 'Thought you might,' he murmured. 'Too early. Adelaide was right.' He saw Rose come around the foot of the bed and his gaze followed her.

'Adelaide?' Eleven's voice was sharp.

'You remember, or you should,' said Ten, still looking at Rose. 'She told me someone needed to stop me. But I didn't listen.'

'And the Master?' said Eleven very quietly.

If Ten could have shrugged, he would have. 'Killed him. Straight off. No second chances. Should've done it ages ago. I wasn't going to bother about any bloody prophecy. Knock four times? Hah! It would have stopped me completing the paradox machine. Stopped me from getting Rose back.'

Rose shivered. This Doctor had killed so very casually just for her? She edged away from the bed and backed up against Nine. She felt the comforting warmth of his arms encircling her and she felt so grateful that she did not question that this action was unusual for her own Doctor. She leaned against him only peripherally aware of Eleven giving them a sharp glance.

Eleven reluctantly stopped scrutinizing Nine and Rose and refocused on Ten who still resolutely stared at Rose. 'What,' he asked slowly, enunciating every word, 'was the last thing you saw Adelaide do.'

'Nothing. She went into her house. She was alive and I'd done it. I showed Time it was not my master and I left in the Tardis.'

'She went into her house?' repeated Eleven. 'You're absolutely sure? Nothing else?'

Ten shook his head impatiently. 'Nothing else.' Then he paused. 'Come to think of it, there was an odd noise, but I didn't bother with it. Didn't seem important. There were better things to think about. Rose to save.'

'She didn't need saving,' Eleven snapped. 'She is alive and well and you know that. And that noise, by the way, was the sound of Adelaide killing herself. The sound of her restoring the fixed moment in time. Remember? When did she die?'

Ten thought for a moment. 'November...' His voice trailed off. He finally took his gaze from Rose and stared up at Eleven. 'She still died? I didn't save her at all?'

'No, you didn't.' Eleven sat heavily down on a nearby stool. 'I tried, but I learned my lesson that day. Adelaide saving me from going down that path to madness. But you didn't learn that lesson and you kept going. And that's it. That is where we diverged.'

'It must be.' Ten stared up at the ceiling, his eyes wide with horror. 'I didn't save her?' he whispered to himself.

Nine looked from Ten to Eleven and back again. 'Adelaide Brooke?' His eyes widened and then he nodded slowly. 'A moment where the Universe is in flux. A fixed moment changed, and you two changed with it!'

'Split apart,' whispered Rose. She moved forward from out of Nine's embrace. 'But... two of you? How did it happen?' She looked at Ten, but he was lost in his thoughts. She turned to the other two.

'Ah,' said Eleven. 'Well, you see, there are different universes, parallel universes, each where maybe just one person makes a different choice, and history changes. You don't know about that... yet. But you'll get there. Now, the multiverse is made of an infinite number of these universes. But here, during that moment before Adelaide shot herself, our universe was in flux. I think Ten here chose to go into the Tardis a moment earlier than I did and he did not hear her kill herself, or at least didn't realize she killed herself. I heard it, realized what it meant and came to my senses. Well, sort of.' He coughed. 'That's a long story. But he didn't and he went on to choose to bring you back and alter another fixed moment in time. One is enough to shatter time. Two? The universe could be destroyed, and no one would be left to pick up the pieces.' He clapped his hands together and rubbed them briskly. 'So, you see, two realities-him and me-that should be in different universes. Only we're not. We're here. Both here. Which is not good. Not good at all.'

He brought out his screwdriver with a flourish and a flick of the wrist and scanned Ten from feet to head. He peered at the readout, holding it so close he was almost cross-eyed, and then scanned himself.

'The strange thing about it,' Nine said to Rose while he too was being scanned, 'is why, after Adelaide shot herself, the universe didn't restore them to one single Doctor-back to whatever the original time-line should be. Why are there two realities within the same universe?'

'The paradox machine.' Ten's voice was heavy. The others turned to look down at him.

'You made that later,' objected Eleven.

'No, I didn't. I started reassembling it on the way back from Mars. Didn't you?'

Eleven clenched his fists and then released them. 'No. I thought about it and even looked at the components, but decided to wait until Adelaide and the others were home.'

Nine stared at Ten. 'It was active before Adelaide killed herself?'

This time, Ten's voice was very quiet. 'Yes.' He turned his head away, a look of guilt on his face.

Nine held out his arms and then dropped them with a jerk of his body. 'Fantastic. You two alter a fixed point and you-' he whirled to face Ten,'-start up a bloody machine that just happens to make sure both of you continue to exist in the same universe.' He looked at Rose then. 'You picked the wrong idiot to travel with. If I'm going to become one or both of these two, I'm going to drop you off back with your mother.'

'You can't!' cried Rose, echoed by Ten. He struggled wildly against the restraints.

'Don't you dare,' growled Eleven. 'She's also a fixed point. You don't like what we did? Fine. We deserve that. But you alter anything about your time with Rose and you do the same thing we did.'

Grudgingly, Nine nodded. Ten relaxed and let his head rest against the pillow. Rose sidled over to Nine and reached out for his hand. He grasped hers immediately and, through the handclasp, she could feel him calming. She covered his hand with her other and massaged and stroked it comfortingly-as much for herself as for him. Ten watched them hungrily.

Rose took a deep breath. 'So, what happens now?'

'Simple,' said Eleven. 'We have to stop the machine. The universe must be restored to whatever it was meant to be. It can't be controlled. The longer the timeline goes with the machine, the more catastrophic the consequences will be if the machine fails. If and when.'

'It could just reverse back to the beginning,' said Ten.

'Great,' said Nine. 'Just in time for you to make your choices again and all this happen again. Infinite loop.'

Eleven leaned over and whispered in Ten's ear. 'Don't forget, no fixed point had been changed before the Master started the machine on the Valiant. We queered the pitch when we saved Adelaide first.'

'Yeah,' said Ten. 'Right. And besides, we'd still be in the causal eye of the storm, so-to-speak. We wouldn't reverse since we're in proximity to the machine. Don't you worry there, Nine. No infinite loop.'

Rose looked at Nine. 'They talking about spoilers?'

Nine nodded dourly.

'Only problem is, we can't get to the machine,' said Eleven. 'Your Tardis doesn't recognize Nine or me. You'll have to destroy it.'

'Yeah,' said Ten. 'I'm the only one who can do it.'

'Right,' said Eleven and leaned over with his screwdriver to sonic the chains on Ten's hands.

'Only I won't.'

Eleven froze.

'What?' thundered Nine. 'Haven't you put it all together yet?'

'Yes,' Ten said defiantly. 'Doesn't matter. I need Rose. I have to have her. This is the only way I can do it.'

'Even by keeping up this artificial time-line?' shouted Nine. 'You're willing to destroy the entire universe for your own selfish needs?'

'Absolutely!' Ten's eyes gleamed. 'You can't stop me. The machine is in place, the Tardis knows what she needs to do, and she will try again. Rose, the right Rose, the one who knows me, the one who loves me, will find her way in and free me.'

Nine strode over to the bed, shouldered past Eleven and planted his hands on either side of Ten. Bristling, he leaned over until their noses were almost touching. 'She will never get in here. Eleven and I will stop her.'

'And how long will you keep that up?' asked Ten. He smiled and Rose shivered at the maniacal, gloating expression that appeared so easily, so quickly. 'Even if you stop Rose, the Tardis will only answer to me and you can't destroy her or the machine.' He looked at Nine and his smile broadened. 'Besides, you won't be able to stop Rose. We loved each other. Once I regenerated from you, we...' He laughed. 'It was..."fantastic", as you might say. Nothing you ever would have seen. She would never have loved you like she loves me. I mean, look at you!'

Nine struck Ten across the face.

Ten gingerly straightened his head and worked his jaw slightly. 'Don't worry, Rose,' he said. 'He knows the truth. Remember, I was him. I know him better than he knows himself.'

Nine lunged but Rose clung to his arm. 'Stop it,' she cried.

Ignoring them, even though both of them were only inches from his face, Ten looked sidelong at Eleven. 'I added some defense mechanisms it didn't have last time.'

'Which are?' asked Eleven.

Ten sighed theatrically. 'Wouldn't you like to know. But you shan't. Though, I daresay, you found out at least one of them already. And I assure you, the state of temporal grace exists. Fully restored. I felt it was necessary since I thought that you might pop by. And there is no changing it.'

Nine pushed himself up and away from Ten with a jerk. He paced across the room and back again.

Rose stood by Ten's side. He looked up at her longingly. 'Why are you doing this?' she asked. 'I've learned enough. I won't come here in the future. Not if you ever look like you. Only for him. "Nine". I can't let you destroy the universe. I can't!'

'You don't have to,' he said diffidently. 'They can't let you out of here with your memories intact. You would alter time just by knowing part of your future. They pride themselves on not being mad, I imagine. I'm the mad one. So they will preserve your time line and erase your memory of this encounter and put you back where you were. Perhaps they've even told you this. Or maybe they were just going to do it on the sly.'

'They told me,' Rose whispered.

Ten looked impressed. 'Good for them. At least they were being honest. Something you have to know about us. All of us. We lie. They wouldn't like to tell you that, but I have no such qualm. Qualm. I like that word. Q-q-q-uallllm. No qualms for me. You won't remember this anyway, so it won't matter for you. But I can face you. I can be honest. Well, honest about this. Well... mostly honest.'

Eleven spoke from behind her. 'I hate to interrupt your moment of honesty, but I must. Sorry, Doctor, but there is one way we could stop you.'

Nine joined them but he stood away from Rose. 'You have monkeyed with the Rassilon Imprimature so the Tardis won't recognize us. But once your current incarnation is gone, it will revert back to the regular setting.'

'The Tardis won't continue without a Time Lord if there is any way she can have one,' said Eleven, 'unless you were cruel enough to force her to stay alone for the rest of her existence.'

'Figured it out, have you?' asked Ten. 'No. I would never do that to her. But let another Time Lord take her with the paradox machine running? Not a chance! She is set for self-destruct if I should die.'

'Or regenerate,' said Eleven. 'You forget. She only recognizes your current incarnation.'

Ten looked at Rose for a long moment. She looked back at him, puzzled by the sudden intensity of his gaze. Finally he looked away and spoke.

'No. She would recognize it if I regenerated. I made sure she would accept a new incarnation if I went through regeneration.' He took a deep breath and then looked at Eleven challengingly. 'She will only self-destruct if I die.' He paused and looked at Nine. 'If you kill me. Completely. That is the only way you can destroy the paradox machine. Are you up to it?'

~ o ~ O ~ o ~

'You can't kill him! You can't!'

Nine, Eleven and Rose had returned to the Console Room. The altered light bathed all their faces in a reddish glow. Rose stood with her back to the paradox machine. Eleven stood awkwardly at the top of the ramp leading down to the door. Nine paced around the machine and the console. He returned to the other two, leaned against the railing and crossed his arms.

'He said it himself,' said Nine. 'It's the only way.'

'No, it isn't,' cried Rose. 'You've got to change his mind!'

Eleven came forward and gently cupped her shoulders in his hands and leaned down a little, eye to eye. 'I'm sorry, Rose, but he won't. I remember how I was before I came to my senses. I remember how I felt. How I...' He swallowed. 'He's gone too far down that same path, and he knows it. Learning about Adelaide shook him. Now he's torn between getting you back and the knowledge of what he's done.'

'You mean... you mean he's asking...?' Tears came to her eyes.

'The compulsion is too strong. He can't stop it. He's gone mad. There is only one small part of him that can fight back, and he's using it. Why do you think he was goading Nine here so much. He wanted to make him angry, to make it easier for him. He would never have been that cruel otherwise.'

'He wants you to kill him?' Rose clutched at Eleven's arms. 'How can he ask that? You can't... There's no way you could... That would be horrible!'

Neither Eleven nor Nine said anything, but looked at her sorrowfully. Tears streamed down Rose's face and she gripped Eleven's arms even tighter. 'Don't kill him! Let me try! Maybe I can convince him...'

Eleven let go of her shoulders and drew her head forward. He chastely kissed her forehead and then let go, pulling away from her. 'You can't,' he said softly. 'You're at the wrong time and he knows it instinctively. Deeply. He wants his Rose. Your future self. All his mind is fixed on that. And... I know how he feels. Felt. But he mustn't be allowed to get you...her.'

Rose sagged against the mesh weave of the paradox machine and slid to the floor. 'You are going to murder him?' she whispered.

Nine knelt before her. 'We have to. The Universe is wrong. This is the only way. There should be only one Doctor. One Tardis. One reality. This is the only way we can restore the Universe to rights and keep everyone in it the way they ought to be. Whichever way that is.'

Eleven looked sidelong at Nine, but Rose did not notice. She pressed on. 'And you can do that? You can actually do that?'

'Yes,' said Eleven. 'And I've done worse. Rose, you sometimes wondered why I wouldn't tell you things when I was him.' he pointed his thumb at Nine, 'Well, this is why. I-we-have had to do some things that we can't-just can't-tell you about. Ugly things, but necessary. For the greater good.'

'For the greater good,' whispered Rose. 'I think I hate that phrase.'

'So you should,' said Nine. He paused and then reached out and stroked her cheek with the back of his fingers. 'I have to take you back now. You shouldn't see any more of this.'

'No,' she cried immediately. 'No! Hang on. You'd be killing yourself in the future. And... and you!' She snapped her head towards Eleven. 'What would happen to you? You're a part of his future... or something.'

'Schrodinger's Cat,' said Nine flatly.

'What?' Rose stared at him disbelievingly. 'Whose cat?'

'The real question is,' said Eleven, 'what will happen once the paradox machine is destroyed?'

'What do you mean?' asked Rose. 'Stop this. Just tell me what will happen to you.'

'I don't know,' answered Eleven. 'As Nine said, it's Schrodinger's Cat.'

'Schrodinger's Cat is,' said Nine, 'a theoretical experiment in which a cat is placed in a box in conditions where it might or might not be killed by chance. A 50/50 percent chance. I won't bore you with the scientific explanation of the conditions.'

'The point is,' said Eleven, 'that we wouldn't know, without opening up the box, whether the cat is alive or dead. One could say that, at any given point, until the cat runs out of air, that is (and that's not part of the conditions Nine mentioned earlier), the cat is in a state of being both alive and dead. It is a theoretical conundrum of existence that has engaged and challenged scientists and philosophers for centuries. And will for millenia more.'

'How horrible!' cried Rose. 'What happened to the poor cat?'

'Theoretical only, Rose,' Nine gently reminded her. 'And the point is, no one ever found out. You can't ever find out, for it would be a 50/50 percent chance, and the whole question is based on the state of not knowing. Not having looked inside the box. The duality of existing and not existing.'

'As the same person, Ten and I saved Adelaide and broke a fixed point in time,' said Eleven. 'In that state of flux, he and I diverged through our different choices. Now we are two realities in this one universe only because the paradox machine is now maintaining that very duality even after Adelaide killed herself and ended the state of flux. Are we symbiotically dependent on each other for our existence? It doesn't matter which one of us created the machine. Fact is, we both continue to exist because of it. Will the Universe treat that duality as one entity and erase me from existence at the same time as Ten and the paradox machine are destroyed?'

'Because he dies, you have to be dead?' asked Rose.

'Exactly.'

'Or,' continued Nine, 'will the Universe take up Eleven's time line and allow it to continue alone, accepting one single time line as a viable and natural state despite the fact that it was created within the same symbiotic existence as Ten's-this Ten's-was?'

'That's the 50/50 chance?' Rose looked at each one of them stunned.

'Yes,' they said together.

'So you don't know if you're going to die too?' Her voice rose. 'You can just stand there and say that? How can you?'

'The alternative would be to put the entire Universe at risk.' Eleven's voice was hard. 'I could never do that. He can, but I can't. I won't.'

'So you will sacrifice yourself,' she muttered, deflated.

'50/50 chance, Rose,' Eleven said, his voice gentler now. 'Those aren't such bad odds. I willingly take them.'

'As would I,' said Nine.

His blue eyes were kind but she knew he was resolute. Both Doctors were.

'And now,' Nine continued, 'it's time to take you home.'

'Not yet! I want to say goodbye to him.'

'You won't remember him,' objected Eleven. 'And then you will meet him for your first time when Nine regenerates.'

Rose jumped to her feet, almost knocking Nine back. 'He will remember. He did all this-' and she waved her hand expansively behind her, '-for me, yeah? It will mean something to him before you... you execute him!'

Nine straightened and looked at Eleven. A long moment passed and then both turned to Rose and nodded, each in their own fashion.

'It will,' said Nine softly. 'Go to him.'

'But keep it short,' said Eleven. 'For both his sake and yours.'

Rose took a deep breath and walked quickly from the room.

~ o ~ O ~ o ~

His eyes were closed when Rose entered the sickbay. She remembered how expressive his brown eyes were, accompanied by his quicksilver moods. Soon this vibrant man would be dead, someone she didn't know but who knew her perhaps better than she knew herself. Soon he would be killed for loving her, even if he had come to love her in her future and too much for his own good. She shivered and crossed her arms, clutching her upper arms with her hands. At some time in her future, her own Doctor would become this man...

Suddenly she quailed and began to turn.

He opened his eyes then and very softly said, 'Rose...'

She froze, her back to him, and she heard him again. 'Rose...'

She turned around slowly to find his gaze fixed on her, those large, chocolate-brown eyes staring as if trying to greedily take in every detail, every possible moment, and commit it to memory.

'I'm sorry,' she blurted.

'I know,' he said, quite calmly considering he was still staring at her so intently.

'They are going to kill you.'

'I know,' he repeated, and Rose didn't know if it was her imagination, but a small flicker of relief seemed to cross his face.

'How can you say that,' she shouted. 'Destroy the paradox machine! Live your life! You don't need me.'

He shook his head. 'I can't. You don't understand-'

'Yes, I do,' she shot back. 'You're being stupid. How could you possibly want to kill yourself over me? That's crazy.'

He smiled at her fondly then. 'That's my Rose. Says it like it is.'

'Stop it!' She wanted to shake him, but he was strapped so tightly to the bed that she realized it was a futile gesture even as her arms had begun to reach forward. She dropped her arms to her sides, breathing heavily.

'Rose,' he said, 'Don't worry about me. I've brought this on myself. This-what is going to happen-is the way it should be. Just accept it.'

'I can't,' she whispered.

'You can,' he said softly. 'It's the only way out for me, and very soon you won't remember this anyway. Just accept it, for me. Please?'

She stared at him for a moment and then her shoulders slumped.

'Thank you,' he said. 'Now, go. This is hard on you and I don't want to hurt you. Go.'

Furiously, she blinked away tears that suddenly filled her eyes.

'Go,' he repeated, 'before I... I lose control. I don't want you to see me like that.'

She hesitated and then came forward to kiss him on the forehead. But at the very last second, she impulsively moved down and touched her lips to his. He eagerly responded and pressed against her. Chastely and respectfully, he did not open his mouth to her, but he caressed her lips with his own as if exploring every part, cherishing the contact. Searching, lingering, gentle kisses touched everywhere and Rose's heart broke at the desperate tenderness.

Trembling, she severed the contact and stepped back.

'Go,' he whispered. 'Don't look back! Go.'

'I...'

'Go!'

She fled, and from behind her, she heard a howl of grief.

~ o ~ O ~ o ~

The Ninth Doctor touched his fingers to Rose's temples, and she fainted, memories permanently erased. He caught her and held her close as he took her back home at the precise time he picked her up. He laid her ever so gently on a bench around the corner from the Powell Estate, where she could wake up none the wiser.

He returned, and he and the Eleventh Doctor brought the Tenth Doctor to the console room. They kept the chains on his hands and feet for they could not risk it otherwise.

Ten stood there defiant, gazing up at the paradox machine intertwined with the console. Slowly, he looked back down and levelled his gaze at the two others. 'You are right to bring me here,' he said. 'You will need to run for that door as soon as you have killed me.'

'Instant self-destruct,' stated Nine. 'How kind of you to warn us.'

'You're welcome,' Ten answered with a glint in his eyes. 'Now do it. Just do it before I try to stop you.'

So they did it. They made him kneel and they held their sonic screwdrivers, one to each of his hearts. Nine and Eleven looked at each another, took a deep breath and then both met the gaze of Ten before pressing the buttons. It was mercifully quick. He slumped over and they gently laid him on the ground.

Nine and Eleven ran. They pelted towards the door as a fireball blossomed out behind them. They wrenched open the doors and were yards away before the shock wave of the final explosion threw them to the ground.

~ o ~ O ~ o ~

Stunned, Nine lay sprawled face down in the snow, his arms flung up to protect his head. Every bone in his body ached from the impact of the shock wave, but he knew that soon it would pass. He lay there weak and trembling. His ears felt partially deafened from the blast and the wind howled over the desolate waste. He could not hear any sounds of Eleven stirring over the din even if there were any.

He could look up any moment now. He paused. The answer was there waiting for him. What would his future be? Did Eleven lie beside him, similarly stunned? Or were there only drifting eddies of snow? He did not want to look up. Would this be the moment he learned of his own future death, or would he be reassured of his own continuing timeline? A 50 percent chance either way. One other possibility had already been erased, destroyed along with the paradox machine, Ten and his version of the timeline. But now it was down to Schrodinger's Cat. Would the embers of the Tardis still be burning behind him, or would it all have been erased entirely from existence? Was Eleven still there or not?

Nine looked up.

The End