The memory starts in the console of the TARDIS, a room that looks quite atmospheric and very sci-fi. Clothes are strewn about on the floor, clothes that are obviously the Doctor's. There's a half eaten bowl of fish fingers and custard on the center console, the large steering column not moving. And in the room? The Doctor and Clara. But it's not this Doctor, it's the younger looking one with a bowtie, the previous regeneration, the Eleventh Doctor.

"Doctor," Clara exclaims, with a smile, as she walks towards him. But she stops, looking over at the Doctor, who gives her a small, tired smile in return.

"Hello," he simply says.

Clara puts her hands together, fiddling with her fingers, as she adds, "You're young again," smile still on her face. "You're okay. You didn't even change your face."

"Ha!" the Doctor laughs, smiling still. "It's started. I can't stop it now, this is just the reset." He starts to walk around the console, talking with his hands as he does so. Clara's face falls. "A whole new regeneration cycle—ooh!" Spotting that half eaten bowl, he puts it to his lips and drinks some of the custard, which makes Clara laugh. "Taking a bit longer," the Doctor continues as he sets the bowl down. "It's breaking it in." Walking over towards the center console, he makes a few noises of discomfort, obviously a bit annoyed before he flips a switch and pulls a lever. The center console comes to live with a whirring noise, as two large circular portions above the console spin in concentric directions.

"It all just disappears, doesn't it, everything you are, gone in a moment, like...breath on a mirror." The Doctor continues talking, using his hands, looking at a very obviously worried Clara. But the Doctor's still smiling, a bit gently. "Any moment now, he's a-coming."

"But who's coming?" Clara asks.

"The Doctor."

"You? You are the Doctor."

"Yup," the Doctor responds, obviously distressed, pain in his voice. "And I always will be." He raises a hand: it's started to glow, pulsing with regeneration energy. "But times change...and so must I." Clara's about to cry. The Doctor turns his head, looking up towards the staircase as if he's seen something. Obviously happy, he smiles. "Amelia!"

Clara looks around, obviously confused. Nobody else is there. "Who's Amelia?" she asks.

"The first face this face saw," the Doctor continues, looking at nothing, spinning in a light circle. It's obvious he's hallucinating. There's a pause, before he continues, attempting to reassure the still rather distraught Clara. When he speaks, it's slow and deliberate and he's still talking with his hands...but he's also smiling. "We all change. When you think about it, we're all different people all through our lives—and that's okay, that's good, you gotta keep moving, so long as you remember all the people that you used to be." Clasping his hands together, the Doctor continues. "I will not forget one night of this—not one day." He winks at Clara slightly, holding up one finger. "I swear. I will always remember when the Doctor was me."

He gives Clara a small nod—she shakes her head. Clara's eyes are filled with tears, she's about to cry at any moment. Again, the Doctor looks up towards the staircase. There's a moment of realization in his face, as he gently smiles at...nothing. Another hallucination. He reaches out, as if he's touching someone's face, but no one's there. Clara takes a few tentative steps forward. Slowly, deliberately, the Doctor removes his bow tie, letting the fabric drop to the floor. He gives Clara a small smile, then afterwards squinches his eyes in pain.

"No, no," Clara can't help but call out, almost in tears as she walks towards him. She offers her hand to his still-glowing one. "Please don't change," she implores, almost under her breath. The Doctor gives her the same weak, pained, but still a hundred percent sincere smile...and then it happens. The regeneration takes a second tops, as a loud whoosh of energy rings throughout the TARDIS. The Doctor's body glows bright for a second as he arches his back. When he straightens out and stops glowing, it's not Bowtie No Eyebrows the Eleventh Doctor that was there earlier: it's Angry Granddad, the Twelfth Doctor, who's staring at Clara with a mixture of shock and confusion.

Letting out a small gasp, Clara backs away from the Doctor who just...keeps staring. They look at each other for a moment, both perfect pictures of confusion. The Doctor takes a few steps forward towards Clara before he rapidly backs up, hand going to his abdomen as if he's in pain. Any sort of solemnity of the moment is ruined as the Doctor yells, "Kidneys! I've got new kidneys!" And yep, that is 100% the Twelfth Doctor's voice. Clara is looking at this whole situation with a perfectly confused look that expertly telegraphs her thoughts: what the flying fuck is going on. The Doctor stands straight up, frowning slightly as he continues. "I don't like the color."