He's taken Donna to a UNIT Christmas party—entirely against his better judgement, mind. Frankly, he could think of about a hundred fifty-seven things he'd rather be doing than hanging round a bunch of soldiers, and he's listing them under his breath as Donna drags him by the hand through the crowded office.

It's bright, loud, and obnoxiously cheery, which Donna appears ecstatic about but which the Doctor doesn't care for right now. He knows that half these people are still armed, even off-duty, because he keeps catching whiffs of gunsmoke and ozone from some sort of energy weapon as he weaves between them. It's making him a bit uneasy, even more so than the overly-loud music and the fact that he can feel the minute vibrations of the floor caused by too many people moving about at once. Too many people, too many smells. Too many timelines, prickling at the edges of his senses.

He doesn't want to be here. He really doesn't. But Martha invited him, and Donna accepted for him, so here he is.

He finds Martha, and she's with R– no, no, Micky, and they're sipping drinks by the makeshift bar. Hers has an olive in it and his has two green beans, which the Doctor doesn't understand in the slightest, but he hugs them both anyways and asks for whatever Donna's having. It's fruity—as predicted—sour and astringent and sweet all at once. It burns his tongue and his throat, sets his taste buds on edge. He wants to ask for a water, but by the time he's got his bearings back—some of them, at least—the bar is nowhere to be seen. He's not sure when they left.

Wherever he's got to now (doesn't really matter where) there's this beat, at the very bottom of whatever song is playing, that keeps catching his ear, dragging his attention away from whoever (doesn't really matter who) is talking at the moment. His fingers tap along with the steady, thumping bass line, his mind picks apart the frequencies as his body attunes itself to them. He feels it, through the soles of his trainers, to the exclusion of every other feeling. The sounds beneath it pull him in too: the cacophony of footsteps, the deep hum of the building's inner workings far, far below. It's soothing. It wants to put him to sleep, wants him to close his eyes against the onslaught of light and sound and smell and touch, and hide.

When it stops, the song giving way to something vaguely jazzy and off-kilter, he feels an irrational surge of anger. Then his ears find the plucked quarter-note tones of the string bass, and he calms once more.

It's only when he stumbles upon a dark(er) corner, entirely by chance, that the Doctor realizes he's lost Donna. Martha and Ricky too. And… he thinks he might've been talking to a group of– of scientific types, perhaps. He doesn't want to leave to find them, doesn't want to turn around and face the fluorescent lights and the hastily-hung neon signs (now he thought of it, had he even come here with them?) and where does one even get those? I'd like one. Perhaps in the shape of an ice cream cone. It could go in the workshop. I'd like a sign. I'd have to put a nail in the wall, though, and… he's not sure why he thought that was an issue.

I'd like an ice cream…

He leans into the wall, resting his forehead on the cool metal. Focus, he scolds himself. His hearts are beating much too fast, he realizes abruptly. His breaths are coming quick and shallow. He feels sick, the smell of gunsmoke and ozone burning at the back of his throat and making his stomach turn. He hadn't even noticed. Somewhere in the distant reaches of his mind he understands what's happening, where he is, what he has to do—but the rest of his mind is not nearly as functional, feels more like it's full of cotton than thoughts, and those few thoughts he can grab at are dominated by the desire to curl up with his hands over his ears and cry. He wants to drag himself back into the room, wants, desperately, not to stay trapped in this purgatorial middle ground between reality and unreality. He just doesn't want it desperately enough.

He stops noticing again, returns to the pleasant—though dizzying—blankness that awaits, mindless of how the colours shift and detach themselves around the edges of his vision, mindless of how shadows that shouldn't be there—count the shadows, shadows that cut (he checks to see whether he's still got his own)—swim amongst the crowds of people, obscure their faces. It's wrong, to surrender like this. It's unnatural. Sick. He supposes he must know that.

(If he cares, he doesn't realize it. It's better like this.)

Someone—Donna—found him, he realizes, huddled in the corner, in the dark.

"," she said.

The Doctor blinks.

She repeated it. Upon realizing he hasn't understood, she adds a tentative, "."

He wants to understand. He wants to reply, so badly it brings tears to his eyes. He doesn't. The lights and colours are all he can see, really see, now, and Donna had still been talking but he can't hear it—it hadn't been the latest bass line he's found, so it's noise—and her words caught in his ears and his catch in his throat. He doesn't want to see her, for she probably isn't real, anyways—a figment of his scattered and witless imagination, and he couldn't bear it, if she hadn't been real, he couldn't bear it…

He closes his eyes. The afterimage burned onto his eyelids is just as bright as the lights.

Until it isn't.

His awareness swims in and out for a long time, his mind playing back images of the party, sounds of chatter and music, interspersing them with what he's really (he thinks) experiencing. But there's something there he can't attribute to a party: a cold, sweet wind that ruffles his hair and his clothes, and it wins out in the end. There's no light from which to shy away, no gunsmoke to stop him taking countless deep, calming breaths. No longer being pushed away, the Doctor finds himself returning of his own accord.

He knows, now, mostly, how he got here, up onto the roof of the office building, though he doesn't quite believe he was the one to do it. He shakes out his hand—how lovely, to remember one has limbs—brushes it through his hair, focuses on the feeling. He's got the capacity to do that now, funnily enough; he's focused enough to focus. He looks around.

Donna is seated beside him, both of them on some sort of vent or other protrusion—what sort of things protrude from roofs?—and though she looks a bit… off, what with the shadows and the colours, the Doctor finds himself willing to ignore it for now.

She notices him looking, and offers a smile. "You alright?" she asks quietly.

The music and voices of the party are distant, dulled; it's nearly silent up here. He takes a deep breath, revelling in the feel of the cool night air, and nods.

"Good." Her eyes sweep over his hunched form, worry hidden just behind her gaze. "What happened, Spaceman?"

The Doctor opens his mouth before realizing that his entire being rebels against the idea of creating more noise. He gives her an apologetic look and raises his hand to his throat.

She nods. "No worries, then."

Flashing her a grateful little smile, he holds out his hand and she takes it, squeezing reassuringly. The contact is more comforting than anything else; he's shaking and weak, his mind is still fuzzy and his thoughts don't quite click together, but her presence is something to latch onto. A handhold he can use claw his way back.

"Y'know," she murmurs, "you could've told me you didn't want to go."

He frowns, cocks his head.

"You didn't say it," she assures. "I just guessed. Not… really that hard, honestly."

He nods. Shrugs.

"It's no fun if you don't like it."

The Doctor doesn't really reply, but after a moment of consideration he leans in to nudge her with his shoulder: a silent show of appreciation. She nudges him back.

After a long while just looking out at the city lights, she turns to him again.

"You look tired," she says.

He feels tired too.

"Ready to head back to the TARDIS?"

Hesitating, he casts a glance at the door to the stairwell.

"It's quiet," she promises. "I, er… I took you all the way down the hall first. You didn't want to stay. We're on the other side of the building."

The Doctor searches his memory, and finds only the vaguest recollection of that part. What he does remember is the paralyzing panic and disorientation, his only respite the feel of her hand in his. He looks down at her, wondering whether the fondness warming his hearts is reflected in his face, and wraps her in a gentle hug, presses a kiss to the crown of her head. That's a sure sign he needs a rest, he thinks—he gets a bit too candid when exhausted.

Donna takes his hand again, her thumb brushing over his knuckles. "C'mon then," she says softly, and leads him away.

It's only once they get back to the TARDIS that he realizes they've abandoned the others. Though he's sure he could speak now, if pressed, he grabs a sticky note off the console and scrawls out a rapid Martha?

"It's fine," says Donna. "Remember? I went down and said goodbye, a little while after I brought you upstairs."

Oh. He hates these gaps in his otherwise-impeccable memory.

Sorry, he writes. Distracted.

"It's alright." She places a light hand on his shoulder. "Just go get some rest, okay? We can always try again."

Dread sends a chill into the pit of his stomach; she's trying to send him off to bed, he knows, and he can't stand the thought of letting her out of eyesight, not when she—everything—still looks and sounds and feels all wrong. He grabs her hand before she can turn and walk away, looking at her with wide, pleading eyes.

"Doctor?" she asks.

The Doctor hesitates, warring with himself. Then he picks up the sticky note and writes out Are you real? with unsteady hands. He shows her, though he does have the presence of mind to feel embarrassed.

Donna understands. "Yeah," she murmurs, "yeah, I'm real. I swear, I–" She takes his hand in hers, squeezes. "See? All real."

Senses, the Doctor knows, can be deceived. He's been around the universe a few times, seen all manner of false realities and hallucinations, holograms and replicas. He doesn't know what to believe, doesn't even know what the most probable answer is, for if everything else is false then surely the statistic would be too, and–

He stops himself. Takes a deep breath. How do I know? he scribbles out. These are fears he's never voiced, and he hopes this doesn't count.

Donna's expression fills with sadness. "You're just gonna have to trust me on this one, Spaceman," she whispers. "Just for a bit."

If she isn't real, he supposes, only half-joking, then what reason has he to feel this vulnerable? He nods, sniffles as tears of exhaustion and relief prickle behind his eyes, and pulls her in for another long hug.

"Thanks," he manages, hoarse and quiet. "Will…" He clears his throat. "Will you stay?"

"Course. Course I will."

She tightens her hold on him, as if she can physically keep him in the room with her, and he smiles—it's only so long, he supposes, before she succeeds.