The Doctor and Rose. Rose and the Doctor. The companion and the magician who showed her the universe. The man and the girl who kept him sane.

The first time he met her, she had a boyfriend named Mickey Smith and she was a shop girl and he'd grabbed her hand and said "Run."

And they had. Rose and the Doctor, in different world another universe over, had run.

Rose had grabbed hold of her Doctor's hand then and refused to let go and the two of them ran from the beginning of the earth to the end and danced and laughed and sprinted about in the middle bit.

The Doctor loves the running and doesn't much like the middle, but he'd stop there for Rose. He'd stay for Rose, and Rose would run for The Doctor, all the way to the end, even if she wasn't much one for endings, herself.

They ran together until they couldn't, until they were out of breath separated by a void and Daleks. They never caught their breath, but they still ran, alone, glancing back every now and then and reaching for that phantom hand (even though the Doctor thrived on never looking back, he did, for her) that they'd once held with such fierce passion.

It's a little different, everywhere. In the whole of space and time, there are more than simple parallel worlds, and there a trillions of those.

But she was Rose Tyler and he was her Doctor and Bad Wolf had changed the very atoms of life because she didn't want her Doctor to be alone.

And in another time, and another space, another where, another when, the Doctor works in the psyche world of Torchwood General Hospital in a war torn earth.

That's where this story of the Doctor and Rose is, on this post-appocalyptic world after everything is gone to shit, and the Time Lords haven't burned but neither have the Daleks and The Doctor is just a human.

This world is a mess, had been ever since Harold Saxon and the war(s) that never stopped breaking out and the Doctor was one of the few people left caring. One of the few doctors-lower-case-d, or healers, or therapists left. Because everyone living wouldn't let themselves care anymore; they were dead inside or they were dead outside and that was the only way to be.

People like the Doctor, people who cared didn't last long.

In this world, the Doctor doesn't run. It seems wrong. But this is a Doctor that can't run, that's trapped on a burnt shell of a planet, working for the mental health department at Torchwood General Hospital.

Rose Tyler was the Doctor's oldest patient still alive and uncured, a schizophrenic in a deluded world of peace and travel through space and time.

He'd met her in an alley on his way home from work, when things were better off and his home wasn't yet destroyed, and she'd said, "Run with me," and she'd grinned, grabbed his hand and the Doctor went and they ran.

It didn't take long for the Doctor to see the imaginary world Rose had trapped herself in, wrapped around herself like a blanket. It was a world of aliens and time travel and adventure and "really wild things". The Doctor barely had time to think, before Rose ran into a cluster of angry men, looming out of the shadows.

And then, they weren't running anymore, because Rose was yelling and telling them to leave the planet and peace and then the Doctor was turning and asking them in a much politer tone to please leave them, he's a doctor – "the Doctor," Rose corrects -, thanks a bundle.

The men didn't leave, and with everything that had – was still, though everyone acted like it wasn't – happened the Doctor wasn't a complete fool.

No one went outside without a weapon these days. Mostly, guns, but the Doctor had refused anything more dangerous than a Taser.

Rose called it a sonic screwdriver and the Doctor pretended he didn't think that was cute.

The Doctor thought that Rose was brilliant, thought her world was almost as beautiful as her and wouldn't lower her to cute. He cried for the first time since the war when he found out her world was a defense mechanism for witnessing the murder of her family while a prisoner of war when she was seven.

She'd been released after the war, only, because able soldiers were more valuable than messed up little girls and it killed the Doctor that the world was just ex-soldiers and victims and too few doctors, all damaged.

He'd started going by the Doctor after that, and he never stopped.

The Doctor met his most … contestant patient, Captain Jack Harkness, through Rose. All of the Doctor's patients either recovered or died or gave up and descended into madness, but Jack was an anomaly.

Rose was sort of an anomaly first, but the Doctor thought with two minds she could get better and waited for her inevitable death to destroy him.

Jack had been a captain in the war and when it had ended, he had drifted, utterly lost and confused, until Rose brought him to her Doctor.

Rose liked to escape the hospital, and wandered off, and the Doctor always had to run around looking for her, but when he found her and she smiled at him, the Doctor couldn't breathe. Jack had clung to the Doctor with the same desperation as Rose, with the hopeless dead eyes that lit up when they saw the Doctor.

Jack, the Doctor didn't diagnose until too late, was bi-polar.

And when Jack was high, was on the maniacal upswing, he too could see Rose's world, the one with the adventure and aliens.

The Doctor didn't realize it at first, how messed up Jack was, how deep Jack's monsters ran.

But Rose did. Rose's subconscious did, at least and tried to warn them. Rose tried to warn them, right up until it was too late and Jack brought his monsters into Rose's world and people were still dying in the real world but the Doctor didn't care because there's only so much pain a man can take and the three of them were in the wreck of what the monsters had left of Rose's world, laughing, laughing, laughing at nothing until Jack started crying and Rose started dying with her world and the Doctor finally admitted something was wrong.

Rose pointed out Jack's demons to the Doctor and the Doctor saw. He gave Jack meds and Jack kissed him, kissed Rose, knowing he couldn't enter Rose's world without the crazy.

The Doctor wondered what that said about him.

Weeks later, the Doctor got a notice about the good Captains failed suicide and passed the case wordlessly to the new doctor, Martha.

The Doctor tried to avoid Rose and her world, but it was Christmas and he couldn't anymore and when he went back (it was always a when, an inevitable when, never an if) she told him he was wearing pinstripes and high tops and she gave him a trench coat and said "for Jack."

The Doctor didn't want to tell her that he wasn't coming back.

But Rose would notice and so he told her that Jack was dead (and he was, to Rose's world).

And then they rebuilt it. They ran together, escaped and rebuilt Rose's world. They missed Jack sometimes, and the Doctor would make up elaborate stories about Jack's infamous sex drive and it would almost like he was still there.

Patients came and went, with their delusions and problems and the Doctor and Rose saved them all. They were the Torchwood tag team, and with Rose, the Doctor helped eighty percent more patients, and forgot the ones he couldn't because Rose didn't like him wallowing in his guilt.

There were a lot that he couldn't save.

There were more that he would never get the chance to.

Everything was going well except – and god, if the Doctor didn't just hate himself for thinking this – Rose started getting better. Kept talking about Torchwood and how Mickey and her dad were gone, lost in an alternate universe.

And real life raged as new battles broke out in the post-apocalyptic hell they were living in and so the monsters and the patients kept coming.

Everything was okay, though. It was fine.

Until Rose started her new medication.

Until it didn't work. Or worked too well.

Until Rose remembered and woke up.

Until the denial stopped and the truth sent her reeling to her death.

The Doctor gave her the meds, he knew. The Doctor killed Rose Tyler, handed her the execution pills, ripped her from her world, and damn if that wasn't a problem no matter how he looked at it.

Rose Tyler, the Doctor knew, was dead (much as he pretended it was a medically induced coma, much as he refused to let her go).

Rose's last words, first words upon seeing the real world had been "I love you, Doctor," sweet and innocent, until the pain and the darkness and real life came and the screaming began.

And it destroyed her, ripped her apart from the inside, and all Rose did was scream a terrible heart wrenching scream as her body writhed in pain on the bed. "It can't … it can't … it's not real!" Rose wasn't often coherent.

Wherever she was, the Doctor would listen and write them down in his journal, so he wouldn't forget a single thing that Rose said.

The other doctors at the hospital forced her into a medically induced coma after twenty-four hours and the doctor finally slept, right by Rose's bed, in her new, dusty, jagged, half-hospital room.

After that, after Rose, the Doctor worked numbly with Martha, became friends out of exhausted necessity and similar situations and completely failed to notice when she fell in love with him (or maybe she always had been).

Jack showed up again. Asked the Doctor why he did this too him, why he couldn't fix him back, and the Doctor told her Rose was dead and he was wrong and never looked back.

Jack was 51/50'd (locked up for 72 hours involuntarily for being a danger to yourself - or others, but that wasn't Jack anymore) over a dozen times in the passing year before he just … stopped.

The Doctor is a coward, was a coward, will be a coward, and doesn't look into why.

He remembers when he wasn't a coward, when he would look for Rose in the ruins of London and how they'd always find each other and an adventure. Finally, the Doctor thinks of all the people they'd saved just by being there, and he can't bring himself to stop.

It can't be half bad, the Doctor knows, because that's how he meets Donna Noble.

And Donna Noble had actually told him no.

Donna had berated him, said she didn't need help, thanks and stop talking nonsenses, no-please.

The Doctor had been too stunned to do anything else.

He didn't see her again, until weeks later when she showed up at the hospital, shouting for the Doctor and proceeding to verbally assault all the workers who aren't the Doctor or patronize her until she finds him.

"Help," she says this time.

Then her legs give out beneath her, and the Doctor notices that her hair isn't just a brilliant shade of red but was also bleeding profusely.

Their relationship was spotty like that. Donna had anterograde amnesia – her mind was encoding memories, but she wasn't able to access them the next day. But it was stupid, because her hypothalamus was barely damaged and sometimes she could.

Sometimes, Donna remembered.

When things got rough (as they always did) he'd take her to Rose's world. He'd show it off, take her to solve mysteries with Agatha Christie or become gods in Pompeii or listen to the song of the Oods.

But exploring Rose's world without Rose was hard and Donna kept slipping further and further away.

Only two weeks later the hospital was attacked.

Calling it a hospital, really, is an inadequate description. It's really more stacks of concrete cells that aren't yet completely blown to bits.

But it's night and there are no electrical lights, because the sky is lit with bombs and the hospital with explosions and the Doctor doesn't even know who it is or why they'd do this. But that is what earth has become: chaos and death.

Rose defies science and illustrated a medical miracle in pulling herself back to consciousness, back to the Doctor, and back to the real world.

The bombs no longer mattered to the Doctor, nor did the pain or the suffering of everyone, not for that moment when he was allowed to see Rose, okay, again.

Rose grinned and the Doctor grinned back and they ran.

They run into Captain Jack and Donna and Martha and the dean of medicine, Harriet Jones, jumps in front of a bullet meant for the Doctor and dies alone, while the Doctor, Donna, Martha, Jack and Rose escape.

Sarah Jane, stage four cancer patient, is in a hospital bed outside the doors, and it's clear she's dying even before the bomb hits and showers her in chunks of plaster.

Nobody is grinning anymore and everyone is shooting now, at everyone else, and the Doctor is yelling. He's yelling "Stop," and "Don't," and "God, everybody just think for a minute – think about this for just one minute". Because they were the generation born into war and fighting is all they know, no one hears him.

No one listens.

Until Donna.

Donna, grabbing control of the hospital PA system. Donna, scolding everyone. Telling them off. The Doctor starts to smile as the people start to listen as the people stop the fighting and the killing. There's enough of that, thank you.

"Oi!" She is saying. "This is a hospital," she is saying. "These are people," she is shouting, "You are people!"

And then she's not.

And then she's falling, bullet through her side.

And then everyone's shooting again, and they're shouting and angry but the Doctor is running at Donna.

She's dead when he gets there.

In Rose's world, he thinks as the shots and cries of the dying ring out, it would have worked. Talking, words, peace would have worked in Rose's world.

And the Doctor cries.

Donna, he knew, if she ever woke, (she won't) wouldn't ever remember how utterly brilliant she was. He thinks that's almost worse.

He thinks that he's never getting Donna back again, and when he looks up, Rose is crying too.

"Run?" She asks.

But they don't run. They get caught with bullets, holding hands.

In the end, when it's all over, Jack is the only one left and with a steady hand, he systematically lifts the gun up to head and pulls the trigger.

(Minutes later, when help comes, they manage to pull off a miracle and bring Jack back. The Doctor's bloody hand stuck in his. He gives up trying to die then.)

Years later the hospital is rebuilt, and the world is starting to get the preliminary idea of maybe possibly getting back onto its feet sometime in the next century at least.

Somewhere, sometime, everywhere and everytime seems to whisper "I love you." The Doctor's last thought, that he'd never said it.

In another universe, in somewhere far away and right there, there's a girl who's glowing and a man with multiple faces and she's explaining, explaining that she knows the Doctor in her world loves her, even though she never said it. She's saying that he's lonely, her Doctor, because she's out here with him – and she likes that, she assures him.

She just misses the aliens.

The man laughs and time laughs with him.

Her other Doctor is lonely, she says, but she'll give him friends. And then he won't be lonely, but she'll be jealous so he's going to change, going to add another face and is that okay?

"I love you," the man says to his glowing girl, his bad wolf, and the earth, the stars, the universe seems to say it with him, echoing love in that one eternal moment.

And the two glance down at the blood spattered earth they just left and reflect that none of it mattered, because in a post-apocalyptic world, they managed to find a happily ever after.

And then the time lord and his time girl float past on the gentle currents of seconds, and minutes and hours. And the two slip away into time itself.

Sometime, somewhere, a man regenerates and a blond baby is born.

And the universe seems to whisper as one:

Run.