A/N: I know this has probably been done a bazillion times before, but it was in my head and just wouldn't leave me be until I'd written it. Hope you enjoy! (And by 'enjoy' I of course mean have endless feels.)
I (most unfortunately) do not own Doctor Who.
It feels like every part of him is on fire. He knows if he can just make it back to the TARDIS, it'll all be over. It's the last thing he wants, but he's beginning to think he'll do anything just to make the burning stop. The Doctor has never held off a regeneration this long, and the fire is so intense that he's nearly blind with pain.
He's said his goodbyes, taken his final reward for saving the world again. He's looked upon his dearest friends for the last time. Donna and Wilf, Jack, Martha and Mickey, Sarah Jane, and of course, Rose. He saved Rose for last, because he knew if he saw her before the others he wouldn't be able to stop looking at her.
"I bet you're gonna have a really great year."
She gives him her blinding, beautiful smile, and she runs off, intent on celebrating. He wonders if his goodbye has affected her timeline; if the Rose he had to leave in Pete's world remembers seeing this face before she even met him. The Doctor wonders, but he'll never know.
The fire's getting worse now as he staggers toward the TARDIS. He stumbles and falls, sprawling in the fresh snow. For a moment he just lies there, burning, when he senses eyes on him. He lifts his gaze to see Ood Sigma, standing there in the snow, eerily similar to how the Doctor had last seen him.
"We will sing to you, Doctor. The universe will sing you to your sleep."
He hears the music in his mind, and it's lovely and sad and heart wrenching, yet it gives the Doctor the strength to push himself up, find his footing, and force himself onward to the TARDIS, his teeth clenching in determination.
"This song is ending, but the story never ends."
He pushes through the door, the Ood's song ringing through him, and he manages to find some measure of peace in it. He moves slowly toward the console, removing his long coat and tossing it aside. The pain rages, and he knows it'll be any second now. He starts the engine, not bothering to set a destination. He supposes she'll tell him – the new him – where she wants to go.
As he steps back and sees the glow beginning in his hands, he takes a shaky breath and allows himself a parting plea to the universe.
"I don't want to go."
The energy is rushing, burning through him, and his breathing deepens, turns ragged as his hearts race. In the last few seconds of consciousness his current mind will know, he knows just a bit of comfort in Ood Sigma's final words to him. As the regeneration energy overwhelms his body and begins rewriting everything he is, he finds his last hope in knowing that, though his piece of the story has come to an end, the full story will go on.