The first time it happens, she is drunk and he is jealous.

She staggers a little as they slip away from the Grand Ballroom. The party is winding down, into an apparently pan-Galactic end stage of slow music and couples clinging to one another.

"You should probably take your shoes off," says the Doctor waspishly.

He's probably right. They are asymmetric silver blocks that looks more like space shuttle spare parts than footwear. They complement a dress that is Victorian governess in shapely structure and positively space-age in material. She looks like an extra in a Lady Gaga video, but fabulously so.

"If I am entirely honest… I'm not sure how." She can't quite remember the instructions the little green woman in the shop gave her when she was strapped into them, hours ago now. They felt fine when she was dancing. Now, faced with a long walk to her chamber, she is suddenly aware of a heat in the balls of her feet. Her ankles ache. Combined with the slight spin the hyper-vodka lends to her surroundings, walking is quite an effort.

"You do realise we've got three flights of stairs to climb?"

She makes a face. "No. Seriously?"

"It's a castle, Clara. Of course there are stairs."

"Yes," she argues, aware she's moving rather more sideways than forward now, and gently rebounding off the wall. "But it's a crystal castle in space. You're telling me they built ballrooms with glass ceilings that look out onto gas nebulas, but they didn't think to install lifts?"

His unamused expression apparently indicates this is so.

She pouts. "But I'm a Princess."

"Yes," he agrees, looking very much as if he is regretting this particular cover story with every fibre of his being. "Yes you are. Princess Oswald. And that's why you have a bedroom in the Fuschia Spire, as befits your station."

She comes to a stop, leaning against the glowing corridor wall for support. "No, it's no good. You'll have to fetch the TARDIS and give me a lift."

"The TARDIS is not a taxi service." He says it with the kind of severity he normally reserves for crazed alien dictators.

"Look, I am not the one that put me in these shoes. You needed me to get us in here and look like we belonged. These shoes are… well, they're your fault."

The signs are not promising. He is surveying her with something very close to contempt.

"You really can't walk?"

"No."

He sighs, deeply, weighing up his options. And then he sweeps her off her feet.

It's not as romantic as it sound. She almost head-butts the wall, instinctively lurching away as he lunges for her. She's not at all sure of what he's doing until she finds herself in his arms, one hand curled around his neck.

"Thanks," she squeaks.

"Don't mention it." He risks a glance down at her, face like thunder. "Seriously, don't. I'm already regretting this."

They move in embarrassed silence for a few minutes, uncomfortably aware of how close they are to one another, as he carries her up crystalline staircases. Outside, behind glass windows of cathedrallike proportion, the nebula twinkles. For a moment she forgets the awkwardness of her position and marvels at the sight.

"I found out where the Nobility plans to hunt tomorrow," she says, attempting to keep things business-like, as if he carries lightly inebriated companions about all the time.

"The Aldebaran asteroid park," he supplies.

"Yep." She pops the p, trying to control her irritation. "That's the one. How do you know?"

"I hacked the Crown Princes' scheduler."

"Then can I ask why you needed me to talk to him all night?"

"I needed a distraction," he replies, as if his answer is obvious, "And what better distraction than a beautiful stranger arriving to flirt with Prince Pudding-Brain?" He says flirt like it's a dirty word, but even drunk she catches the compliment. A flush creeps into her neck. Probably the vodka, she tells herself. "Anyway, it didn't seem like much of a hardship."

"I was doing what you asked!"

"Oh yes. Selflessly sacrificing yourself at the altar of seducing an attractive man."

"Doctor…" She resists the initial urge to slap him silly; he might drop her. Anyway, she has a better weapon. "Are you jealous?"

He scowls down at her again. "Why would I be that?" As if the question is ridiculous. Her weapon turned against her; she feels unexpectedly wounded by his contempt for the very notion.

"You smell of bananas," she says grumpily, aware it's not the most cutting of insults.

"That'll be the daiquiris."

He kicks open a set of double doors and carries her into her chamber. It is a vision in pink crystal and gold veneer, gauzy drapes framing the biggest bed she has ever seen in her life. He dumps her onto the silken sheets unceremoniously, whipping the sonic screwdriver out of his pocket.

"What are you doing?" she asks, uneasy, as he points it at her legs. The answer is immediately obvious as her shoes unbuckle themselves, falling from tired feet onto the floor with a very solid clunk. "Oh. Thank you."

"My pleasure."

He is staring at her, waiting for the next line, inscrutable. She has no idea what he wants. "What?"

"The dress."

Her hand clamps down on the neckline instinctively as he brandishes the screwdriver. "What about the dress?"

"Do you need that unbuckling too?"

"Um." It's a fair question. She gives the fastenings, hidden in the fabric somewhere under her right arm, a cursory examination. "No," she manages, slightly strangulated, "No, I think I can manage these ones."

"Good. Right." He hesitates for a moment, hands flapping, and then lies down next to her on the bed.

Ram-rod straight, with his hands folded in his lap and boots still on his feet, the move is hardly an obvious overture. Nonetheless, it marks a first for the Doctor, who claims to not need sleep.

"Er,"she manages.

He opens one eye. "What?"

"Why are you in the bed?"

"I'm resting. Obviously."

"But you don't need sleep."

"Not normally, no. But I want to metabolise the alcohol I was forced to consume this evening to maintain cover. It'll go faster if I do it lying down."

A horrible suspicion presents itself for consideration: that the Doctor is just as drunk as she is. She supposes it's a mercy they didn't fall down the stairs.

"It's a big bed," he continues, "More than enough room for two. I won't be any bother. I'll just lie here very quietly and let you get on with sleeping."

"Oh. Right. Okay then…"

He shuts his eye. She watches him for a few minutes, breathing deep and even. It's a passable impression of sleep, or at least deep meditation. She turns her attention to her dress. Some of the scaffolding is poking her in the ribs and it needs to come off. She turns away from the hopefully sleeping Doctor and fiddles surreptitiously with the fastenings. This goes on for some time. To her mounting horror the dress is at least as complicated as the shoes.

He sighs. "You can't unbuckle that either, can you?"

She debates, briefly, the merits of hitting him with one of the shoes. They're quite solid seeming. They'd probably hurt. "No," she eventually admits.

"Would you like some assistance?"

"Maybe," she replies, through gritted teeth.

He sits up behind her, his fingers brushing against hers on the fastenings. "Yes, it's quite a complicated one," he says quietly. The breath that carries his words stirs the hair on the back of her neck.

She blushes again, and hopes he doesn't notice.

"Are you blushing?"

Of course he notices. "No," she lies.

"Why would you be blushing?" he asks. "I'm not being rhetorical, by the way."

She makes a noise of frustration. "Doctor, stop being deliberately dim. You. My friend−my good friend−my totally alien but very definitely male friend… You. Are undoing my dress."

"That's such a human way of looking at things," he huffs, "There's plenty of species where this is completely acceptable behaviour between friends. The rest of the galaxy isn't half as… as sex-obsessed as you lot are."

"I am not sex obsessed." The pressure on her ribs eases. He has unfastened the dress but his hand is still resting lightly on her back, as if he has forgotten about it.

"I'm not blaming you," he continues, in that special tone of voice he has that suggests he probably is. "It's a species thing. I'm just saying not everyone out there is as crazed about it as humans are."

She leans back against him, his hand slipping to touch the inch of bare skin he has revealed. She can feel the staccato double beat of his hearts through his chest. His pulse jumps when she turns her head.

"Are you seriously telling me," she whispers, almost into the crook of his neck, "That you're not thinking about it at all right now?"

He looks down at her, almost nose to nose. "No."

She's not sure what he means, that's the trouble with the Doctor. He could be answering her question, or he could be telling her to stop this dangerous line of enquiry altogether. She could pull away now, turn over, go to sleep. Pretend this never happened. Keep things under control.

"No?"

His fingers shift, ever so slightly, tracing the skin over her ribs. "I am… Thinking." The rest of the sentence is lost as her lips meet his.

She expected tentative, exploratory, but he kisses her like the world is about to end.

"Thought so," she grins, when he briefly surrenders her mouth.

She is unsurprised to find, when she finally wakes up, that he is gone.

Her dress is neatly laid over the chaise-lounge, shoes paired on the floor beside it. Something slightly less formal and probably acceptable daytime attire has been hung up for her on the dressing screen.

It could almost have been a dream. Perhaps it will become that for both them, in time. A moment's extra madness, set aside from the day-to-day reality of their impossible life together. Right now, lips bee-stung from all the kissing and muscles aching sweetly, it is still very real.

There is a glass of water on the side-table and what looks very like two Alka-Seltzer tablets. She pops them into the glass, enjoying the fizz for a moment, and notices the note.

Clara,

For the hangover.

When you're done sleeping your life away, come and find me in the shuttle bays.

Doctor

Perfunctory, concise. Tiny bit rude. But he's never left a note before and she knows it's his way of saying he has no regrets, either.