Work Text:
With the Fam off on one of their walkabouts, the Doctor went looking for that galaxy she’d shrunk down and meant to put back. A thorough search of two libraries failed to produce the orb, but it had definitely been on her desk at St. Luke’s... So she just hopped back on her own timeline to grab it.
The Doctor’s old office was just as she remembered, like she’d only just stepped out. Momentarily distracted by the photos on the desk, she completely overlooked the other person in the room.
“Nardole, have you seen―?” Bill Potts jerked up from where she’d been bent over a bench by the window. “Oh Sorry! I thought you were― He’s out today! I’m Bill.”
“Bill?!” The Doctor gawked at her former companion. After a few beats, she realized she was apparently supposed to say something else. “Er. Who’s out?”
“The Doctor,” Bill said, gesturing around. “He’s run off somewhere. Sorry.”
“Oh,” the Doctor said. “Right.” Had she always been so bad about leaving companions lying about? Jumping back on her own timeline was bad enough, but running into an old companion could make the TARDIS all kinds of sick. She could already hear her grumbling about it.
“Anything I can help with?” Bill chimed in, interrupting that thought.
The Doctor gave herself a mental shake. “Nah, I was just… uh… dropping by. Thought I might’ve left― Oh, there it is!” She spotted the sphere sitting next to the sonics. “I knew I’d seen it around here somewhere!”
Bill blinked at the sphere in question. “You left that here? I thought it― Hold on, hasn’t that been here for months? How’d you remember to come back for something you left in here that long ago? I can’t remember where my shoes are from yesterday.”
“Oh, I’ve a good memory for things like this,” the Doctor bragged. She held the ball up to the light so that Bill could see the translucent effects of the trapped star system. “Looks like everyone’s accounted for.” She tossed it up, caught it, and shoved it in her pocket. “No harm done, as the kids say.”
Bill gave her an odd look up and down. “Er. How do you know the Doctor? Are you close?”
The Doctor cast about for an acceptable answer. “Ohhh, we’re… fairly close, you could say.” She caught another odd look from Bill. “Wot?”
Her companion startled and looked away, suddenly sheepish. “Nothing!”
The Doctor had never seen Bill sheepish before. “Are you all right?” She looked as physically fit as ever. Bill really had been in the prime of her life. The thought made the Doctor unbearably sad, even years later. “You know, someone as young as you should really be out having fun. What are you doing holed up in some stuffy old office anyway?”
“Oh, it’s, uh,” Bill gestured like she might catch an answer out of the air. “It’s hard to explain, but…” She gave the Doctor another distinctly odd look. “Guess I could get out a bit… Would you, uh, want to have... I don’t know… a cuppa? Or something?”
The Doctor knew she shouldn’t. Crossing her own timeline was bad enough without witnesses. …But she knew her old self wouldn’t actually be back until well into the next day. And it was Bill. And she’d missed Bill.
It seemed no number of centuries were going to make her any less selfish. “Ah’d love to.” Bill smiled and she smiled back so widely it hurt her cheeks. “Cafe by the main hall?” Bill’s brows went up and the Doctor realized there were two closer options between their current location and Bill’s favoured shop, but… Well, she wasn’t going to take Bill to the student kiosk that she’d always complained tasted stale, now was she? “Best cuppa on campus, right?”
“It’s a date.” Bill smiled at her in a way that she’d never smiled at her before, an odd combination of excited and… shy? No, that couldn’t be it.
The Doctor caught her hand and pulled her along. A few stolen hours wouldn’t ruin any timelines. And it was Bill. She deserved a little treat, every few millennia.
Bill really was brilliant. The Doctor knew that. She’d known that. Even hollowed out after River and Clara, she’d been drawn in to Bill as a beacon of pure promise in amongst the highly mediocre university population. It wasn’t that she forgot how brilliant her companions were, but… well, it certainly was easier to try not to think about it after they inevitably passed.
But here she sat, chatting aimlessly about which courses she hoped to audit in the spring. The Doctor couldn’t remember asking before, in spite of technically being her tutor. In fact… “Did I― did the Doctor ever officially enroll you?”
Bill gave her an odd look. “How do you mean? Do I not look like a student?” She sat up a bit straighter, tugging her brightly-coloured jacket further over her collar bones.
The Doctor scrunched her face in confusion. “Is that an insult? How’d that be an insult?” She played it back in her own head. “Why on Earth would you want to look like anyone else?” Nothing about Bill had ever blended in. It was one of her best features. “You’re absolutely brilliant!”
“Oh,” Bill gave her another incomprehensible look. “Well, that’s― That’s all right then, isn’t it?” She smiled that odd shy smile again. “Er. Thanks, I think?”
The Doctor looked her up and down again. “Are you sure you’re all right? You seem… Do you always smile like that?” She couldn’t remember ever seeing that smile before, and she’d seen it three times over now.
Bill ducked her head and took a noisy sip of her nearly depleted drink. “Sorry. Can’t help myself around a cute girl, y’know.”
“Oh.” The Doctor remembered, quite suddenly, that she looked like a woman now. A human woman. And hadn’t that puddle woman been blonde? “Oh!”
Bill sat back, immediately distancing herself. “Oh, sorry. Was that not―? Was I not―?” She pulled her cup nearly to the edge of the table, as far away as possible without actively getting up and leaving. “Sorry, I didn’t mean to assume. Obviously, I’m not into pressuring… Do you want me to go?”
“What? No!” the Doctor caught her hand before she could get it off the table. “Course not!”
Bill went very still, eyes wide. “Er. All right…?” Her fingers twitched against the Doctor’s wrist, but she didn’t pull her hand away. “I can― Sorry, was that really a surprise? I feel like I might as well be wearing a neon sign that says ‘I like ladies.’” She glanced down and laughed. “I mean look at my shirt!”
The Doctor looked down at Bill’s rainbow top. “Er. It’s nice? Colourful?”
Bill unsuccessfully swallowed a laugh and pointed at the Doctor’s chest. “Is that how you picked your look? Just a fan of colours?”
The Doctor glanced down, baffled. “What is wrong with this top? I like this top! It matches the braces!” She hooked them out with her thumbs to demonstrate.
Inexplicably, Bill found that hilarious. “Are you serious? Did you just wake up from a coma or something?”
“Course not!” the Doctor lied. Humans didn’t need to know about every little nap she took. “I like this top!”
Bill smiled at her in a much more familiar way, like the Doctor was some strange thing that she couldn’t understand. “It’s a really nice top. I like it too!”
The Doctor suspected there was more to it, but at least Bill looked less likely to bolt. “You humans and your limited views of fashion. I’d think by now you’d have―“
“Hang on,” Bill stopped laughing and leaned in. “Did you say ‘you humans?’ Are you not―? Aw, is anyone else at this university human?”
The Doctor choked on her tea. “No, that’s not what I―“
But Bill was already working it out, too clever by half. “Is that how you know the Doctor? Is there some sort of alien convention? Do you trade alien business cards and then pop by for alien visits?”
The Doctor shushed her. “Wot? Course not. Stop shouting about aliens. Humans don’t like that!”
“So you admit it?” Bill crossed her arms, looking smug. “I knew it. Go on then, what’s your deal?”
“My deal?”
“Yeah, your deal! What type of alien are you? How do you know the Doctor? Hang on, do you know the Doctor? Or are you from the half of the Universe he’s already hacked off? What was that ball from earlier? Let me see it again.”
The Doctor dodged Bill’s reach for her pocket. “Hey! Don’t grab! When did you get so suspicious? Not being human isn’t a crime, Bill Potts.”
Bill narrowed her eyes, but didn’t reach over again. “Guess you have a point… Hold on― How do you know my last name?”
“Er.”
“You know I thought I felt― Let me see your hand.” Bill reached for the Doctor’s hand and unexpectedly pressed two fingers in at her wrist. “Two hearts, cool skin, weird outfit― You’re a Time Lord!”
“Wot?! That’s not how you tell a Time Lord―!“
“I knew it!” Bill crowed. “Thought he said he was the last one. Oh, but then there’s Missy too. Hang on―“ She leaned in, squinting suspiciously. “Missy, is that you?”
“Of course not!” The Doctor snatched her hand back. “She’s in the Vault! You think I just let her out for tea? It’s a vault, Bill!”
Bill skipped right past chagrinned and straight to accusatory. “Doctor?!?” She jerked back hard enough to rock her chair. “You do disguises?! Why are you disguised as a lady?! Why are you disguised as a lady and chatting me up?!?”
“It’s not a disguise,” the Doctor chided. “It’s just… what I look like now. You don’t see me getting all fussed every time you colour your face in.”
Bill barreled right past that. “You can just… change bodies?! Was Nardole actually telling the truth about how he used to be a robot?!? Do you two just go around switching bodies whenever you’re bored?!”
“What? No! It’s nothing like Nardole!” The Doctor gave up the game, all too aware she was going to have to erase Bill’s memory now anyway. “It’s… did I ever tell you about regeneration?”
She was fairly confident it hadn’t come up. She was pretty careful not to casually bring it up around the humans. But Bill snapped to attention.
“You died?!?”
Several cafe patrons looked over, startled, and didn’t seem to be reassured by the Doctor’s frantic shushing. “Don’t just shout it out!” she hissed.
Bill suddenly seemed to become aware of the attention they were drawing. “Come on,” she said, and pulled the Doctor up. “Can’t make a scene here. Well, more of one, anyway.”
The Doctor didn’t protest. It’d be easier to erase her memory out of sight anyway.
Bill spun around the second the office door closed. “You’re from the future, aren’t you?”
The Doctor shrugged. “A bit, yeah.”
Bill barked out a laugh. “A bit?!? It really is you, isn’t it?!” She stepped in and the Doctor took an instinctive step back, but Bill backed off instead. “Still not a hugger?” She crossed her arms, broadcasting curiosity. “So how’s it work, exactly?”
The Doctor was still reeling from the attitude change. “Well… new body, new me, basically.”
“But you remember me, yeah?”
“Course I do!” She couldn’t help but be a little offended by the thought. “Same mind, same memories, here.”
“Don’t be offended!” Bill laughed. “It’s not like I forgot to read up― you’re so secretive!” She looked the Doctor up and down, already back to her friendly familiar self. “It’s not bad, this!”
The Doctor couldn’t help but smile. “Bill Potts, I’ve missed you.”
“Aw, yeah! How long has it been? For you, I mean?”
“Oh, it’s… hard to count after awhile,” the Doctor hedged. “I live a lot longer, you know. You humans just…” She trailed off, uncomfortably aware of the last time she’d assessed Bill Potts’ survival rates. “Best not to think about it, eh?”
Bill didn’t look satisfied with that, but she also didn’t look like she was on her way to an existential crisis about her own mortality. “Guess you can’t exactly tell me how long I’m going to live,” she said, somewhat begrudgingly. “Not that I’d want to know, y’know.”
“Best not,” the Doctor agreed.
She started to ask another question, but clearly couldn’t quite get past that. “Er… Hard to think of what I can ask…”
Regrettably, the Doctor knew an out when she saw it. “I should be getting back anyway.” She pulled the paperweight galaxy out of her pocket and held it up to the light to have something to look at. “Don’t want to forget to put this back again. They will be wanting out eventually.”
“Aw, what’s in there?” Bill eyed the sphere much more skeptically than before. “Is it alive? I’ve borrowed that thing for study breaks!”
“Oh, it’s harmless. Just a little suspension of time and space to get around a minor, hardly-worth-mentioning cataclysmic event that I had absolutely nothing to do with.” Bill didn’t look any more convinced than any of her companions ever did after the first trip. “Well, the point is I’ll put it back now. And no one will even notice!” She pocketed the rock with one hand and held the other up. “Come here for a moment, would you?”
Bill was immediately wary. “Why?”
“Oh, it’s just… speaking of paradoxes…” She curled two fingers, beckoning, but Bill looked even less convinced. “Honestly, what is that look?”
“You’re going to try to erase my memories again, aren’t you?” Bill looked just as belligerent about it as she had the first time they’d met. “Is that your solution to everything?”
“It’s not like that first time,” the Doctor pointed out. “I’m doubling back on my own timestream here. The TARDIS can handle a little closed-loop paradox, but this―“
“But I don’t even know anything!” Bill pointed out. “I don’t know when you die, I don’t know when I die. You didn’t even tell me when the next iPhone comes out! It’s not a paradox!”
The Doctor sighed. “Bill, it’s not… It’s not a good idea.” Knowing that didn’t make her any more enthusiastic about having to erase Bill’s memory by force. “Please.”
Bill was clearly gearing up for another argument, but she seemed to lose some momentum over that. “Right,” she said, deflating. “Suppose you’ll have to do it anyway. Guess I don’t want your last memory of me to be me arguing about it…” She took a deep breath and then a stuttering step into the Doctor’s reach. “Right then.”
The Doctor hesitated, thrown by the show of faith. “…It won’t hurt,” she said. Reminding herself as much as her companion.
Bill twisted her mouth to the side, not quite a smile. “Just do it. It’s all right, Doctor. If this is the cost of travelling with you… well, it’s worth it, isn’t it?”
The Doctor swallowed down her response to that, but couldn’t quite get her hands up. “Bill, I’m…” She couldn’t quite apologize, even now. “I’m really glad I met you.”
Bill Potts smiled at her, genuinely fond in spite of the circumstances. “I wouldn’t trade it for anything,” she said and closed her eyes.
The Doctor knew she had to close the loop. “I can’t have you knowing a future version of myself. Even knowing that there’s a future version of myself would be a spoiler.” She’d fought the change so hard this last time.
Bill squinted one eye open and then the other. “I… don’t have to mention it, you know. Not like you ever ask what I’ve been up to. Usually you’re already on about some space thing as soon as you open the door.”
“Oi, I ask what you’ve been up to!“ The Doctor tried to remember the last time she’d done so and started to get a bit of a headache. “Well. You usually just tell me, don’t you? Be a waste of time to ask about something you’re going to tell me anyway, wouldn’t it?”
Bill’s brows went up optimistically. “Total waste of time,” she agreed. “So why would you ask? And if you didn’t ask, and I didn’t say…” Her brows ticked up again, shamelessly hopeful.
“Don’t start with the eyes,” the Doctor griped, but Bill was already well into begging.
“Please,” she tried. “I won’t say anything!”
“Bill…”
“I don’t want you to do it, you clearly don’t want to do it― Let’s just not do it!” She smiled, recklessly optimistic. “It’s nice to know you’ll still remember me, even… however long after I’m gone.”
The Doctor lost what little will she had and held her arms out instead. “Bill Potts, how could I ever forget you?”
Bill jumped in for the hug with a whoop, even lifting her off her feet a bit. “Oh, I like you as a lady! You should come around more often!”
“Bill, it’s still me!” The Doctor jerked back to argue about it and Bill let her go immediately, still beaming.
“Oh, relax. It’s a joke!”
“I can still erase your memories, you know!”
“Nah, you had your chance.” Bill grinned and offered an elbow. “Want me to walk you back to the TARDIS? Even older now, aren’t you, old man?”
“You can’t ask for a trip,” the Doctor warned, already calculating how many short hops she might be able to fit in before the timeline stretched too taut. “Even telling you where we can’t go could create a paradox.”
“Did I say anything about a trip?” Bill pulled on her travelling jacket and flashed a brilliant grin. “Maybe I just want a peek inside. See what you’ve done with the place!”
“…Maybe a quick peek.”