Disclaimer: I don't own the Doctor, Rose Tyler, or any of the comic books mentioned herein.

Author's Notes: My first AU! The bunny bit me and I couldn't not do it. Hope you enjoy.

He knows from experience that the unnatural silence that settles over the room when the bell jingles can mean only one thing: a hot girl has entered the comic book store.

Without looking up, he can tell that she has a boyfriend—everyone snaps back to what they were doing too fast for her to be alone. When he finally does hazard a glance, though, he forgets how to breathe for a second. She's… well.

She's different.

He's well-versed in the behavior of Girlfriend-Dragged-Along-to-Comics-Shop, and she's gorgeous and she's smiling and she's breaking all the rules. She's supposed to hover around the guy she came in with and check her watch, but she's not: she's looking at the shelves in honest curiosity. The expected look of indifference and casual disdain is nowhere to be found, and that's the most beautiful thing of all.

They leave after about ten minutes, but he thinks about her all day.

The second time, she comes in alone.

"Can I help you with anything?" he asks, actually doing his job for once.

"M'fine, thanks," she mumbles, eyes trained steadily on the spines of some old DC trade paperbacks.

"You know," he says, as he's never been very good at shutting up once he's started talking, "You might find some other titles more your speed. Batman can be a bit… dark."

She looks at him, finally, and there's an amused twinkle in her eye that makes his heart beat faster. "Oh, really?" she asks, and it's around this time that he realizes he's made a terrible mistake. "Well then, enlighten me. What kind of a comic would be more my speed?"

He gulps and tries very hard not to stare at her tongue, which is now poking out between her teeth in an obvious effort to give him a heart attack. Aware now that she won't take kindly to any of his intended suggestions (which is silly, as both Spider-Man Loves Mary Jane and Birds of Prey are really good, actually) he stutters for a moment before finally choking out "Superman?"

"Superman," she repeats incredulously. Teasing.

He bristles. "What's wrong with Superman? An alien—the last of his kind—adopting the human race as his own? Form of a man, powers of a god? Epic plots, Lex Luthor, Darkseid… Superman is brilliant."

"Batman's better," she says with a shrug.

He splutters noiselessly, jaw working. "Bat—Batman—'Batman's better?' Name me one way in which Batman is superior to Superman."

"He's human."

"What? But—"

"—but that means Superman is stronger and faster and can freeze things with his breath. Sure. But Batman doesn't have any powers. He's as strong and as clever as he is thanks to years of training, not because Earth happens to have a yellow sun."

"He's also a billionaire with infinite resources. I find that a bit harder to relate to than an orphaned outsider."

"But he's not an orphaned outsider. Call him the Last Son of Krypton all you want, Superman's still as American as apple pie. He never met his parents; he didn't know his people. He may have lost his home planet, but Batman lost his family. They were murdered right in front of him. He became Batman so that no other little boy would have to go through what he went through, and I buy that sense of personal tragedy a lot easier than I do Superman's back-story, thanks."

And quite suddenly he's done being shy around her. He feels confident. More than confident, even. He feels electrified. "You cannot honestly be arguing that Batman's story is inspirational. He's Batman. The Dark Knight? Sound familiar?"

She laughs. "S'all just a front, though. Batman's a terror because Bruce Wayne's so broken; s'why he needs people. Superman's never needed anyone. He likes them well enough, but he's a one-man army. He's nice, but not a team player. On the other hand, despite all of his talk and reputation of being a lone wolf, Batman's got the biggest family of any hero in comics."

He scratches the back of his neck. "I suppose. But—"

"Oi, Spaceman! Whenever you're done flirting, I could use a bit of help over here!" Donna shouts from behind the front counter, and he flinches as reality snaps back into place.

"Go on, then," teases his mystery girl with a grin. "I've got reading to do."

"How's Gotham?" he asks, having slipped over to her side of the store for a bit to (in theory) stock shelves.

"Oh, you know. Dark. Depressing." She's made a comfortable little nest for herself in the back corner, using her backpack as a pillow and her jacket as a blanket. He wants terribly to join her.

"Not 'inspirational?'"

"Not in the slightest. Haven't you heard? Only dorky aliens who think glasses are a good disguise can be inspirational."

And there's that electric feeling again. He doesn't understand it, but he likes it—how being around her makes him feel. Something about her makes him… a bit full of himself, really; her teasing only spurs him to impress her more. "Yeah, well," he says, when it finally occurs to him that she's been waiting for him to respond.

"Listen," she says, "could you watch my stuff a bit? I'll only be gone a minute."

"No problem-o," he grins, then winces. "…and I will never say that again."

A quarter of an hour later, she drops a half-finished order of French fries from the fast food joint across the street at his register.

"Didn't want them to go to waste," she says with a smile.

"…thanks," he says to the air she'd just occupied. He's not quick enough for her—yet.

"But he's so lame, though!" she laughs into the summer night, and her hair glows gold under the streetlamps. "Krypto the Superdog?"

(Somehow "I'm sorry to kick you out, but we're closing" had turned into "can I walk you home" had turned into her grabbing his hand and entwining their fingers, and he has no idea what's going on but it's brilliant, whatever it is.)

"Like Ace the Bat-hound is any better."

"Shut up; that's not the point."

"Isn't it?"

"No!" she insists, but she's grinning and bumping his shoulder and he has never, ever talked to anyone like this before. "The point is that the only thing Superman, Superboy and Supergirl have in common is the S-shield and maybe, depending on the canon, a few genes. But Batman has Robin because he needs Robin."

"A superhero shouldn't need help from a teenage sidekick."

"It's not about help, it's about—"

"Would you do it?"

She stops walking in order to look at him properly. "Do what?"

"Become a sidekick. At our age; not even out of school, no idea what you want to do in life. Give it all up to fight crime and save the world. Would you do it?"

"Would you?"

"I asked you first."

She starts walking again. "…if the right person asked me, maybe. Yeah. Yeah, I'd do it."

"It's an impossible lifestyle," he reasons. "Unsustainable and dangerous and hard."

"S'better with two," she says firmly. "There's nothing wrong with needing a hand to hold. Or someone to stop you when you go too far."

"I'll concede the point. But that's not Batman-exclusive. Superman isn't as alien as you're making him sound. He's fallible."

"'Course he is; he can't see through lead and he's allergic to kryptonite," she snorts.

"I'm not talking about that. All that stuff you said about needing people, that's the same. Kryptonite isn't Superman's weakness. Not really."

"Oh?" she asks, playing along. "What is, then?"

He squeezes her fingers. "Lois Lane."

She swings their hands between them, biting her lip pensively. "I like that. Him needing her. Though, to be fair, she needs rescuing an awful lot."

"So does Robin. But they wouldn't be worth the time if they weren't a bit jeopardy-friendly. He loves her—Superman loves Lois, I mean—exactly because she's the kind of person who'll wander off and get into trouble."

She grins at him widely, tongue in her teeth again. "Guess so."

"How d'you know so much about comics, anyway?"

She raises an eyebrow at him, but her smile never wavers. "What, girls can't like comic books?"

"I mean… sorry. That came out wrong. I just mean that I haven't seen you around before. Well, once."

"Yeah, I was with Mickey. He kind of got me addicted; he didn't mean to."

He tries to drop her hand, but she holds tight to him. "He your boyfriend, then?"

She looks tense and a bit sad. "Used to be."

"Sorry," he says. (He's not.)

"It's… it was a long time coming. We're still friends."

"But that was only a month ago," he says, eager to change the subject. "Seeing you at the shop. Not even. You've learned that much this quickly?"

She smiles and shrugs a bit. "I tend to fall in love easily. …Would you?"

He splutters. "Um, what?"

"…be a sidekick. Sorry, it's just that you never answered."

"Oh, right. I… no."

"No?"

He gives her a cocky grin. "I'd be the hero."

She laughs. "Oh, of course. This is my stop, by the way; goodnight."

Her hand slips from his, she kisses him on the cheek, and then she's gone.

He'd be lying if he said he wasn't looking for her, but finding her again is honestly an accident. The only reason he's at Henrik's at all is because he's pretty sure it's Martha's birthday tomorrow—or perhaps yesterday—and either way he owes her for putting up with him all the time.

And then he happens to glance at the check-out counter and there she is.

"Did you find what you were looking for?" she asks when he finally reaches her register, distracted.

"Yep," he says, popping the P.

Her eyes shoot up. "Oh, my god. It's you!"

"Hello!" he grins, and gives a little wave.

Her face lights up and she stands on tip-toe, trying to see over his shoulder. "Shareen! Shareen, c'mere!" A girl he's never met before wanders over, and is practically dragged behind the desk for her trouble. "Can you cover for me for five minutes? Thanks!"

And before he can get another word in, she grabs his hand and pulls him across the floor to the Petites section.

"I can't believe it's you!" she says, giving him a rushed hug.

He grins. "Nice to see you again too… Rose."

She looks puzzled for a moment, then glances down to her name tag. "That's cheating."

"Or I'm just clever."

She chuckles. "Alright then; fine. I'm Rose, Rose Tyler. And you are…?"

He makes a face, a low whine emanating from somewhere in the back of his throat. "No, I don't want to do it like that."

"Do what like what?" she asks, and he looks at her as if she's a bit slow.

"Names and all of it. Lets… not. I mean, why should we? No rule says we have to. We could… come up with code names instead. Make it an adventure."

"If all this was just an elaborate scam for you to get me to call you Superboy, you're gonna get a smack," she warns, eyes bright.

"Oh, no no nonono no, Rose Tyler. We're far too original for that. I'll be Doctor… Doctor… well, Doctor something."

"Oh yeah; very original."

"Well all the good ones are taken! Doctor Strange, Dr. Fate, Doctor Doom, Dr. Horrible, Doctor Mid-Nite…"

"Doctor Octopus, Dr. Drakken, Dr. Mario, Dr. Quinn: Medicine Woman…"

"You're not helping."

She laughs. "Fine. How about just The Doctor, then, if you're so picky?"

He considers it. "The Doctor. Hmmm. I like it. The definite article, if you will."

"Glad that's settled then."

"But what about you?"

"What about me?"

"If I'm gonna be the Doctor, I can't just go around calling you plain old Rose Tyler."

She wrinkles her nose in thought, and the simple gesture is so adorable that he has to shove his hands in his pockets to keep himself from hugging her again. "I dunno. I've never thought about it."

"I suppose you can stay Rose for now," he offers graciously. "But by the end of the day, I expect us to have come up with a superheroic moniker for you."

"It's only fair," she agrees. "So… what are you doing here?"

He weighs his options. "Would you believe me if I said 'looking for you?'"

"No. Were you?"

"...No. I, ah, I'm shopping for a friend's birthday present."

She clicks her tongue. "Shame."

"Why?"

"We have a personal shopper service here. I'd get a commission."

"Neither of those are answers to my question," he points out, and then the meaning of what she actually said hits him. "Wait, hold on. You want to dress me up?"

"It would be fun!"

"Fun for me or fun for you?"

"Just… fun."

"I'm not a Ken doll!" he squeaks, mortified.

She snorts. "No arguments from me."

He opens his mouth to argue, snaps it shut again, and then settles for a pout. "What's wrong with the way I dress?"

"Nothing! … if you don't mind being mistaken for a U-Boat captain."

"And I suppose you'd rather I dress like Bruce Wayne."

There's a predatory gleam in her eye that would scare him if he wasn't busy finding it incredibly attractive.

"Oh, I love it," she enthuses when he emerges from the dressing room. "I mean, the shoes've got to go, but—"

"Absolutely not. The Converse stay."

She examines him thoroughly a moment, and he pulls on his ear in discomfort. "You know what? You're right," she decides, "They suit you."

"What about this?" he asks, pulling at his lapels. "Does it suit me?"

She cracks up. "I can't believe you just said that."

"Answer the question."

"Yes; you look very dashing."

He inspects himself in the mirror, unfamiliar with his appearance in grayish-brown and pinstripes. "It's not too… Gotham?"

She bites on her tongue. "Would you rather I get you a blue one? Ooh, you could even wear it with a red shirt. Or we could chuck the suit entirely and get you a cape."

"Very funny."

"Few people understand my humor," she says with a shrug.

He can't really afford it, but he buys the suit anyway.

He spends the next few hours half-heartedly searching for something Martha might like and pretending like he's not waiting for Rose's shift to end. After what feels like ages, she emerges—and with a simple "come on, Doctor" (he gets chills when she names him), she takes his hand and leads him to the diner across the street.

"So what are we going to call you?" he asks as they wait for their drinks. (A banana milkshake for him; a Shirley Temple with extra cherries for her.)

"We nothing; I'll create my own identity, thanks."

"Well that's not fair. You already named me; I want to do it," he says petulantly.

She laughs. "Okay, where do we start?"

He considers it for a moment. "Um, we'll… traits. List your traits."

She puts her elbows on the table and leans in. "Oh, no. You're the one who wanted to do this together. No help from me. Go on; tell me about myself."

He gulps. "Well, you're… friendly."

"Thank you," she says; under the table her foot taps against his shin, and he tries not to choke on his own tongue. "What else?"

"You're, um… you're fun. And you're loyal."

"Mhmm," she agrees, tracing patterns up and down his trouser leg.

"And you, ah… like… taking walks?"

Her foot pauses. "Sorry; are we describing me, or a dog?"

He grins. "You, Rose Tyler, would make an excellent dog. Or conversely, a particularly bad wolf."

"That's it!" she laughs.

"What's what?" His cheeks hurt from smiling so much.

"That's my codename: Bad Wolf!"

He furrows his brow. "Isn't it a bit… I'll huff and I'll puff and I'll blow your house down?"

"Don't knock the Bad Wolf, Doctor."

"Don't knock the Doctor, mangy mutt."

"Do you kids need more time?" asks their very miffed waitress as she sets down their glasses, "Because I can come back if…"

They never hear how she ends that sentence; they're too overcome with laughter.

At the end of the day, he saves himself as The Doctor in her phone and she saves herself as Bad Wolf in his, and that's that. (He changes it to 'Rose' when he gets home, though. He'll call her Bad Wolf to her face but never in his head; she's too perfectly Rose Tyler for him to think of her as anyone else.)

Over time, they find a routine. Every weekend he comes by her house in his beaten up blue station wagon, and takes her on an adventure—never telling her where, only occasionally calling her the night before to give hints as to what to pack or whether she needs to wear something special. He puts on his suit for her every time—even when they go hiking or to the beach—and she laughs at his jokes and holds his hand in return.

They do an awful lot of running.

As the summer goes on, she starts to neglect her other friends. Learns how to read his mood by examining the quirk of his mouth; gets in the habit of buying him ties with her Henrik's employee discount. Gets annoyed when he neglects to text her all day and gets worried when he doesn't call her at night. (Always the stupidest, most random things, too. "What if the royal family of Britain were all werewolves?" "Where would you go if you could travel anywhere in the universe?" "Would you rather solve a murder mystery with Agatha Christie or meet ghosts on Christmas with Charles Dickens?" No one's ever wanted her opinion on much of anything, before, and she relishes his every question.) She tells him everything—about her dad and her dreams and her nightmare relationship with Jimmy Stone—and he tells her absolutely nothing at all. Somehow this doesn't seem unbalanced or unfair; she doesn't think she's ever known anyone better.

(And she learned his name months ago, after all—for all his play at secrecy, he's never made an effort to hide his wallet from her. She hasn't told him she knows; she suspects he'd be rather put out if she let on what an open book really he is. He fancies himself a mystery man and, god help her, she loves indulging him.)

Every Thursday he tutors her for the SAT, giving her a hug for each new vocabulary word she masters. She makes him meet her mother and he refuses to let her within a two-mile radius of Donna, and she's never had a relationship like this before—where arguing doesn't mean fighting, and every smile feels like a gift. On a trip to the planetarium, he whispers the names of the stars in her ear along with the narrator, having long since memorized the lecture after countless solitary visits, and maybe this is what falling in love feels like.

"Too slow, Doctor!" she laughs from a few branches above him as they make their way up the tree they've mutually decided is the highest in the woods.

He bites down on a curse as the rough bark scrapes at his palms, and wishes he'd picked anything other than a nice suit as his customary outfit. "Since when are wolves good at climbing trees?" he grits out.

"They aren't; I'm just a really bad one," she calls back, tongue between her teeth. (Objectively speaking, they both know it's a lame joke. That doesn't stop them from using it at every opportunity.)

"Tell me another," he laughs, glad for the distraction.

"Alright. Um… oh! We'll stay on theme. Did you hear about the dogs in Barcelona?"

"What about them?"

"They've got no noses!"

"Then how do they smell?"

"Terribl—"

He sees it like it's in slow motion—how her foot slips as she loses purchase attempting to grasp a higher limb; the way her knuckles go white as she tightens her grip uselessly, balance already lost; the sound her body makes when she hits two branches in succession as she falls the twenty feet to the forest floor.

"ROSE!" He barely recognizes the sound of his own voice. He can't move fast enough; climbing back down from limb to limb seems to take a lifetime. Some distant, rational part of his brain reminds him that he has to go slow; that if he falls, he won't be any help to her.

He's never been so scared in his life.

"Rose," he whispers roughly when he finally reaches the ground, pulling her into a wild embrace. (Only then does he remember that you're not supposed to move someone with broken bones; his panic increases, but he can't bring himself to let her go.) "Oh, God. Rose." She seems so small, limp in his arms—skin rubbed raw and face pale, she's practically unrecognizable as the girl he knows.

She coughs, and his lungs start working again.

"You used my real name," she mumbles blearily as her eyes flutter open. "That's against the rules."

And he can't help it—at the sound of her voice, instinct takes over, and he leans down to crush his lips against hers. For one startled second she stays perfectly still in his lap, but it's only a moment before her brain throws off the last vestiges of unconsciousness and she's able to enthusiastically return his kiss. Her arms wrap around his neck and she tangles her fingers in his hair, and they stay that way until the need for air becomes too great.

"That's… new," she breathes after pulling away, swaying unsteadily. She closes her eyes and rests her head against his shoulder to regain equilibrium, then looks up at him through her lashes with a sheepish smile. "Hello."

"Hello," he replies, voice tender. "You okay?"

"Yeah. Don't think anything's broken. Just… dizzy. Scrapes sting a bit."

He grins shakily. "Sounds like you need a Doctor," he says, and kisses her again.