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The Doctor is over 12 billion years old, almost as old as the universe. Stars have been born and died out since the last time she saw Rose Tyler. And yet, when they bump into each other one day on a nondescript world, the Doctor discovers that she’s not over her old love. Not by a long shot.

Now if only Ten weren’t there...

***

A plastic hamster ball thunks against her nose.

The Doctor groans. She isn’t ready to wake up, not yet.

“Doctor! Wake up, please!”

Her eyes snap open at the sound of her name, immediately settling on the upside-down pink imp in lederhosen standing in front of her inside the ball. Well, not upside-down. The Doctor is on her back.

”Hello, Wankershim,” she says. “Sorry for the mess.”

“Right, you,” Rose says from somewhere near her feat. “Who are you and what’ve you done to the Doctor?”

The Doctor tilts her head and looks up to see Rose brandishing a rather large cannon, pointed directly at her face. “That’s a fire extinguisher,” the Doctor smirks. “Did you sneak that on board while I was in France with Reinette?”

Rose’s eyes narrow. “No, it’s a freeze ray.”

The Doctor rolls onto her side and lifts herself upward. “Fire extinguisher. And I showed you how to use it.” She’s on her feet, and Rose hasn’t even tried to pull the trigger. “He’s fine, he’ll wake up soon. Blistering headache though.” As soon as the words pass her mouth, the pain splits her prodigious brain in half, as if reminded it’s supposed to exist. “Ah!” She grabs her forehead with one hand, staggers into the TARDIS console. Oh, grunge phase. She hasn’t missed THIS setup.

Rose immediately drops the fire extinguisher and rushes to the Doctor’s side to steady her. “What’s going on?”

“Blinovitch Limitation Effect,” Ten says from behind them. “Reapers aren’t the only thing that happens when you cross your own timestream.”

Thirteen can see it, the way Rose’s face lights up, and her stomach leaps into her esophagus at the sight. She’d forgotten that look, and the feeling it brought.

”Doctor!” Rose shouts, racing to hug him. “You’re all right!”

”Course I’m all right. Why wouldn’t I be all right?” he replies with a confused sort of half-hug back. He’s still staring at Thirteen, accusation across his face.

”I thought she’d hurt you,” Rose breathes.

”Nahhhh,” Ten drawls. “Nothing intentional, just the laws of temporal physics! For instance, if I take—”

”I’m not doing that,” Thirteen interrupts, sensing where he’s going with this. “You may be fond of waking up on the floor, but you don’t remember what being old feels like.”

Ten boggles. “Blimey! I forgot what conversations with me are like.” He steps forward to examine her, walking in a way that kind of reminds her of a chicken. “So which me are you? Next? Next but one?”

Thirteen ignores him and stretches out her hand to Rose. “Hello, Rose,” she says. “I’m the Thirteenth Doctor. It’s good to see you again.”

Ten freezes with a look of shock on his face. “I’m sorry,” he says. “Did you say thirteen?”

***

Thirteen, it turns out, has quite the craving for jelly babies, and she goes wandering off with the small pink man she calls Wankershim sitting comfortably in her pocket, gazing out at the rest of the TARDIS. For the moment, Rose and Ten are alone.

”Doctor, what’s going on?” Rose says. “Who is she?”

”She’s me,” the Doctor says with that little excited pout he does when he’s surprised by something but doesn’t want to show it. “Well, a future version of me anyway. I must’ve squeezed out an extra regeneration—”

”You can regenerate as a woman?”

”Oh, yeaaah,” The Doctor says. “One of us—the Corsair—switched genders with every regeneration!” He’s talking to distract himself as much as to answer Rose’s questions; for one fraction of a second, before she knew he was there, Thirteen had left her thoughts unguarded. And the Doctor had seen what was inside her mind when she looked at Rose.

Love... and guilt.

”And what was that thing, back at the bazaar? With the blue lightning?”

”It’s what happens when a time traveler touches their displaced self,” The Doctor hears himself saying, though the vast majority of his brain is still trying to puzzle out what, exactly, Thirteen was thinking that left her feeling so guilty. “Remember when your dad handed Baby Rose to you in the church? We’re lucky you two didn’t make skin contact, we could all have been vaporized.”

Rose grimaces, then leans in close. “Does she, you know...” she giggles. “Monthly?”

Ten smiles back. “Aw, Rose, I can consciously control the rate my hair grows, do you really think—”

He feels the frustration boiling from Thirteen’s unshielded mind seconds before she storms back into the console room, Pycorean prince still in her pocket. “WHERE DID YOU PUT THE BLOODY PANTRY?”