Burning, burning, so burning...

Fire, smoke, brimstone: this is hell, with ash falling like snow falls. Tortured landscape, broken-open mountains belching lava and spewing toxic gases. He runs, because he has to: because he's dying just like this planet is and there's nothing else for him to do.

It's a small planet, trapped in between the shared orbits of two enormous gas giants. They call it Trenzalore, the eleventh planet of its system. The tidal stresses of its unusual orbital position have at last proven to be too much for its weak crust. It is being torn apart. This is hell and it is where he will die.

He doesn't want to die.

Eleven lifetimes of adventure, of friendship, of terror and wonder and everything in between. He doesn't want to die and so he runs. He can feel it creeping over him, changing him. He looks at his hands and sees golden motes dancing between his fingers.

"No," he hisses to himself. "Not like this!"

The fall of the eleventh, they had said; on the fields of Trenzalore, at the fall of the eleventh, the question that must never be answered would be asked. Silence would fall.

And Silence had fallen, all across the universe, all at once. They were gone now, their religion and movement wiped from history, locked away in a forgotten corner of reality soon to fade from existence altogether. The question had been asked and answered and the moment had come and passed and now the fields of Trenzalore are being destroyed and he's dying.

He thinks of his friends, safe and happy, where they're meant to be. Amy and Rory, living out their lives in New York City; River Song, continuing her adventures with and without him; Clara, made whole again. He misses them. He wishes they were there with him, so that he doesn't have to die alone again.

It feels strange this time. Something's gone wrong.

He struggles over a rocky ridge, only for a wave of pain to overcome him. He is driven to his knees, cries out. Golden energy shines from every pore of his body. He's being changed, his genetic code rewritten. He doesn't have to die but he has to change and he's scared.

This is eleventh regeneration but something feels strange.

He hauls himself to his feet. If he can get to the TARDIS, if he can flee Trenzalore, he can find a way to make everything right. It hurts. Every part of him hurts. His purple tweed coat is singed and soiled, utterly ruined. How fitting, he thinks; even his bowtie has been torn off.

"Keep going, Doctor," he demands.

He can't allow himself to die here. He can't let the Silence win. The dark clouds part, allowing the system's distant primary to shine a light on the broken planet. In the distance, he sees the TARDIS, in between two lava flows, shrouded in smoke. Her blue shell is scorched and darkened by soot and ash but she is whole and welcoming.

The feedback from the Machine was so powerful that it overwhelmed his Time Lord anatomy. Cooked him from the inside out. Only the regeneration energy swirling through his cells kept him alive, kept him moving; as soon as he flipped the switch, as soon as he answered the question, it was too late to save himself.

He struggles to walk down the ridge. The heat and the smoke is overwhelming.

Coughing and breathing out glowing golden light, he reaches his ship, his home, his sanctuary and constant companion. He leans against her doors and pushes them open. The console room is dark, its machinery still and quiet. Sucking in a deep breath of fresh air, he realises that his lungs are all but useless, turned to Swiss cheese by the gases outside.

He collapses to his knees and coughs. This time, along with the regeneration energy, he coughs out blood. Thick, black blood.

It hurts.

He looks up at the TARDIS console, at the glowing blue time rotor above it. She knows what to do: she closes the door behind him, a lever on the console is lowered seemingly of its own accord. Then the TARDIS is in flight, spiriting him away from Trenzalore. He swallows away his pain as the regeneration energy begins to glow brighter and brighter and brighter. He is being overwhelmed by it. He's being destroyed and remade.

"Goodbye, old girl," he says to the TARDIS. He smiles. "See you soon."

And then it's all too much. He screams as golden light pours from his fingertips and his open mouth and then he is screaming with a different voice. A new voice. Waves of power shoot from his ruined body, smashing against the interior of the TARDIS. The console is torn apart, the time rotor is ruptured. Roundels shatter. He is lifted from the floor, suspended in the air by the raw power that ripples from him.

Then the light dies and he is dropped unceremoniously to the floor, a changed man.

His shock of dark hair is gone now, replaced by a straight auburn mane that falls over his eyes. He is shorter, slimmer, his hands wrinkled but shapely. As the TARDIS console room lies broken and sparking around him, he drags himself over to the console. Propping himself up, he looks in the darkened monitor.

His jaw drops open.

His new body is all high cheekbones and big green eyes and his face is distinctly, utterly feminine. Laugh lines crease her eyes and her mouth; she is beautiful, mature, wise. "Well," she says, her voice soft and lilting, but still powerful, knowing, "this is new."