Chapter 1: It'll take more than a doctor

"For heaven's sake, Castle. It's only medicine."

Castle pouts. "Don't like it, Beckett."

"What are you, five? You need to take it. Three times a day. You haven't even taken the first dose yet, so how do you know you don't like it?" He droops pathetically at her.

"It will taste horrible. Worse than the coffee you used to have in the precinct. It'll make me sicker. It's like broccoli. Just looking at it you know it'll be horrible."

"Don't be such a baby."

"Where's your compassion? Your milk of human kindness? Your maternal, caring instinct?"

He stops. Beckett has disappeared. The sound of hysterical laughter has replaced her, as if she were a demented Cheshire Cat. He peers out from his cocoon of pillows and covers to find her sitting on the floor, crying with laughter.

"What's so funny? I'm ill, and you're sitting on the floor laughing."

"Maternal instinct? Milk of human kindness?" she gurgles. "Are you doped?"

Castle glares. At least, he would glare, if only his face were suited to it and he weren't suffering so badly.

"What's wrong with that idea?"

"You've been following me for nearly three years and you think I have a single, solitary maternal instinct? You are definitely sick." She struggles up from the floor, still sniggering at the thought. "Now, take your medicine."

"Won't."

That was a mistake. Beckett moves faster than a speeding bullet, pinches his nose shut, waits for his mouth to open for him to breathe and then pours the spoonful of medicine into his mouth. He has a choice between swallowing and choking. He opts to swallow. It tastes foul.

"Done," Beckett says smugly. "That wasn't so bad, was it?" She's humming. The evil, torturing witch is humming. It takes him a moment to recognise the tune.

"A Spoonful of Sugar? You didn't give me any sugar, Beckett. You haven't given me anything to take the taste away."

"You want a lollipop to lick?"

"I'd prefer to lick" –

"Shut up, Castle," Beckett grates, blushing furiously.

" – an ice-cream." He smirks. Even if he feels like a truck ran over him, getting one up on Beckett is worth it. Though her automatic assumption was entirely correct. He would certainly prefer to lick her. If he weren't sick. Right now, Beckett could strip down to her undoubtedly stunning underwear and he wouldn't be able to do anything about it. The thought doesn't even raise – ha! – a twitch. That's depressing.

It's all his own fault, too. If he hadn't insisted on following Beckett around in the rain when he was already feeling a bit rough, because he knows there's something wrong with her but he doesn't know what it is except that she really spooked on the sniper case that they've just finished (and he didn't want to admit to any weakness) and if he'd gone home when he'd really started to feel awful rather than sticking it out until everyone went home, and if he'd not gone in this morning when he felt like hell but wouldn't admit it – well, maybe Beckett wouldn't have been driving him to the doctor because he'd started to stand up and then sat straight back down again a lot more quickly than he'd meant. He must be ill. He can't even think in sentences now.

At least it had been his own doctor. He wouldn't have put it past Beckett – who is being entirely unsympathetic – to take him to the precinct doctor. Still, it hadn't been pleasant. Dr Kovach had poked and prodded him and taken his blood pressure and stabbed him with needles when all he, Castle, had wanted to do was lie down and die quietly. And then he'd been given this revolting yellow medicine and – worst of all – the nurse had told Beckett, who she'd clearly assumed was his girlfriend (but Beckett hadn't denied it, for once, though she'd given him her patent don't get any ideas, Castle look too), to make sure he took it. Three times a day, for a week. First dose immediately he got home.

It was ridiculous. He didn't need medicine. He simply needed sleep. He didn't need a doctor either but Beckett wouldn't listen to his perfectly reasonable arguments and insisted he was going, backed up by the threat of her Glock. The medicine looked vile from the moment it was produced. Sulphur dissolved in urine thickened with cornflour. And it tastes worse than that. He's not ill. He can't be ill, because he's never ill. He has the constitution of an elephant and he is very proud of his good health.

He slumps into his sheets, already exhausted. "Please may I have some ice-cream, Beckett? I wanna take the taste away."

"Okay." He's too tired to be surprised by her acquiescence. He's out before she's left the room.

He'd be astonished if he could see the look on her face when she comes back in, with a small bowl of ice-cream. Chocolate, because there had been three times as much chocolate ice-cream as anything else in the freezer and it therefore seems very likely to be his favourite. Castle's asleep, and for once he looks completely vulnerable: white and ill and his big body somehow shrunken. Whatever she'd said when he was awake, she is actually more than somewhat worried about him. In three years, near enough, he's never been ill, or even a little off-colour. She's never even seen him pop an Advil, though occasionally he's self-medicated his emotions with alcohol.

And now he's out cold. Barely had the energy to put on pyjamas – didn't have the energy to flirt and ask her to help. (She wouldn't have.) Perked up for five whole minutes (she counted) while he complained about the medicine. She sighs. She knows what's going to happen here. She can't leave him. It wouldn't be right. It wouldn't be what partners do. She's a poor enough partner at the moment, spooking at guns and hiding the truth.

Martha's touring, God knows where in the Mid-West. Maybe Oklahoma. Maybe it was Ohio. Anyway, she's not here to look after her son. Alexis is on a school trip for a week. (Why in November? Weather's vile. Must be because it's off season and the costs are low, though she wouldn't have thought anyone worried about costs if they were at Marlowe.) And senior year is really not the time to be missing out on school because you're looking after your father, even if you are normally the grown-up in the house and you'd be happy to do it.

He can't be left alone, and the only possibility left to look after him is one Kate Beckett, currently standing in his bedroom with a bowl of chocolate ice-cream which is starting to melt, a gun and a shield. Only one thing to do, really. She sits down on a handy chair and eats the ice-cream meditatively. Captain Gates is not going to like this. Captain Gates, however, doesn't need to know. Castle doesn't need twenty-four/seven care, he just needs someone making sure he takes the medicine. Oh… and someone here with him in the evening and at night.

She casts another look at him. He looks different when he's asleep, without the exuberant personality and the myriad expressions that dance through his eyes. Of course, the pain crease that hasn't smoothed out from his forehead doesn't really help.

She shuffles the chair – thank heavens it's not an enormous armchair that would scrape the floor and make noise and waken him – to next to the bed, goes to put the ice-cream bowl in the dishwasher, looks at Castle's coffee machine and decides very rapidly that she needs sleep before tackling that monstrosity, fails to find even the poor substitute of instant coffee (even she has some instant coffee for those moments of absolute desperation and complete fumble-fingeredness, how can Castle not?), raids the bookshelves and discovers a book that even she has never read.

Who on earth is Ruth Dudley Edwards? And why does Castle have so many books by her? She makes sure she starts with the first. She never reads the ending in advance, and her absolute pet hate is starting a series mid-way through. It's the same logical, orderly thinking that she applies to her job.

(Castle had once referred to it, early on, as hard-core anal retentiveness. When she'd finished with his ears, he'd promised never ever to say it again. Never, Beckett. Promise! Sadly, she can't torture him for his thoughts. But it's pretty clear that he thinks it, every so often. Hmmm. Mmmmm. Making him take his medicine will be sweet revenge – and she'll be doing it for his own good. Ah, perfect. She can torture him and feel good about it. She hums A Spoonful of Sugar again.)

She doesn't actually need to go back and sit in his bedroom with the book. She could sit in Castle's study (though it makes her just a little uncomfortable to be intruding into his sanctum. Mostly, the discomfort is because she is entirely unsure that she could resist the urge to search it and discover his secrets.) or she could sit in the family room on that sinfully comfortable couch, or she could go up to the guest room, make up the bed, borrow some essentials from Alexis or Martha (she'll skip the Olay, thanks) and read in bed. She really doesn't need to watch over him. Really.

But he's genuinely ill, and clearly belongs to that minority of men who won't admit to illness (most of them make a mild cold into swine flu), so if he gets worse he'll hide it. And that's all the justification she needs. She goes back in, seats herself in the chair to the extremely limited extent possible, and begins the book.

Half an hour later she's decided she adores the book. She's had some difficulty controlling her sniggers at the wry, sardonic humour and the characters, no doubt caricatures but oh-so-worth the exaggeration. She does not, however, adore the chair. It is not comfortable. She can't curl up. She can't tuck her feet under her, or drape her legs over the arm, or lean back. This is not a good chair for reading in. She'll need to tell Castle that. He should have a useful chair in here. If she's going to be spending time in here he should have a comfortable chair for her to sit in.

She glares at the chair, which despite being an inanimate object cringes. It makes her feel better. She leaves the book with some reluctance, and decides that she'd better prepare for bed. That's another problem. Ferrying Castle to the doctor and then home, and then having to stay, had not, surprisingly, figured on the day's to-do list. Going home to a small glass of whiskey to cure the shakes and shivers from the case had. She's done that every night this week. It helps. Not a lot, but she won't have more than one and it does help some.

She knows what would help more. Has known, ever since her last apartment blew up and she had to crash here. But they've never talked about that either. Never talked about how she'd crept down and snuggled in beside him and he'd woken to find her wrapped against him. She'd been awake, when he'd very carefully detached himself so as not to wake her. But nothing had happened, and they'd never mentioned it ever again. Bit like their only kiss, really. They've never mentioned that ever again, either. They're really good at never mentioning anything ever again.

That line of thinking is not helping her get ready for bed. First problem, she has nothing to sleep in. Okay. She's taller than Alexis, and rather differently shaped; and the thought of borrowing Alexis or Martha's nightwear is just – well, icky. Borrowing a t-shirt of Castle's, however, is not icky. Not least because she's done that before too, when she stayed here. She investigates his closet, and when that fails – she'd been sure he'd hang up his t-shirts: he's such a clothes-horse – raids his drawers until she finds them. She's very quiet about it, and he doesn't so much as turn over in his sleep.

Actually, he hasn't moved at all. That doesn't seem very good. But he is breathing – that's a good start – and when she carefully feels his forehead, although he's definitely running a temperature it's not worryingly excessive. Another thing she'd better keep an eye on. At least she's found a t-shirt, which – she buries her nose in it – smells rather deliciously of Castle. That will quite definitely do. Now all she needs is a toothbrush.

She wanders upstairs and borrows some of Alexis's cleanser and moisturiser, finds a spare toothbrush, changes in the spare room, and wanders back down. She tells herself it's to read her book. Mostly, though, it's to make sure that Castle is okay.

She glares at the chair again. It is really not comfortable. Sitting on the floor would not be comfortable, either. There is one other option…

This is a really, really bad idea. It's not fair of Castle to get ill and need looked after. If life were fair then she wouldn't be looking at Castle glued firmly to one side of a truly enormous bed and thinking that the empty side looks astonishingly suitable for sitting and reading. There's a small side light, there are lots and lots of pillows to lean on and it would be nice and warm with her toes under the covers. Castle doesn't appear to be a quilt thief, she notices. No risk that she'd disturb him. And if he does need something, or seem to be getting worse, she'll be right there to deal with it.

Her decision is made for her when she shivers. It is not warm, standing around in a t-shirt in a ridiculously large apartment in November. She wriggles very carefully into the free side of the bed and manages not to get within a foot of Castle. Apart from anything else, she doesn't need broiled. Castle is giving off enough heat to roast a rhino. Could be useful in winter, that. She's often chilled.

Sorry? What? This is a one-time thing because he's ill and she is worried about him. He's her partner. She has a right to be worried. She goes back to the book. Far too late – that is a damn good book – she realises that she should have been asleep two hours ago, and that she will need to get up early to get to her apartment and change clothes. If she packs a bag it'll do for the next few days if Castle isn't better tomorrow. She sets the alarm on her phone and switches the light out. The last vague flicker of consciousness says that this is a very comfortable bed, and a very comforting place to be.

She doesn't think that this is not the bed she meant to snuggle into to find sleep. She doesn't realise that she's reached across the gap to find Castle's hand. She's blissfully, contentedly asleep, in a way that she hasn't been for quite some months.

Castle wakes in the small hours of the morning, feeling atrocious. His head hurts, his joints hurt, his eyes hurt, and he is quite convinced that his eyelashes hurt too. And just to add to his woes, he is hallucinating. It's an astonishingly realistic hallucination, but it is simply that. There is no way that Beckett would have stayed the night, still less in his bedroom, still less than that in his bed. So it can't be real. He must really be ill. Or it might be the ghastly medicine.

There is one small consolation, though. If it is a hallucination, then it won't object if he cuddles up to it, the way he's wanted to ever since Beckett had sneaked into his bed over a year ago – he's still not entirely sure whether it had been due to her nightmares or his – but then they'd never talked about it ever again. Since this hallucination is holding his hand, contact is clearly not a problem. Well, insofar as anything is clear through his pounding head, it's not a problem.

He heaves himself over on to his other side, where he could, if only he could keep his eyes open and his head in one piece, admire the excellent realism of the hallucination: it even has the beauty mark and Beckett's long eyelashes and satiny skin that had felt so good against his… He is definitely ill. But the hallucination will do nicely as a remedy. It's a lot better than vile yellow medicine, that's for sure.

Heaving complete (he is fuzzily sure he's actually lighter than two years ago: running round with the cops has inspired him not just to books but to a proper fitness regime, but right now he'd swear he weighs a couple of tons, one of which is possibly his head), he pulls this wonderfully solid hallucination into him, shuts his aching eyes and slithers back towards sleep.

Two hours later he wakes up again. He hurts a little less, but that might well be because he's still hallucinating. In fact, he's even further into complete insanity because this time his hallucination is talking in its imaginary sleep. Certainly proves it's not a real Beckett, that. She never talks about anything important when she's awake and he's sure she wouldn't do so in her sleep.

"Want to get better, Dr Burke."… Definitely not Beckett. She never goes to the doctor. And she isn't ill. He's ill. Beckett made him go to the doctor, which was simply not fair.

"I don't wanna talk about it. I just wanna be better."

So does he. He's never ill. It's not fair that he's ill and Beckett made him go to the doctor and made him take horrible yellow medicine that's making him hallucinate about having a Beckett in his bed who's talking. He'd pout, but it would make his head hurt even more. He'd kill for a Beckett in his bed, and he'd kill for a Beckett who might actually talk to him.

"I can't have him till I'm better."

What? This is insane. This is definitely a hallucination. He cuddles down and firmly closes his eyes.

From a prompt by Mobazan. "It's only medicine." Said by Beckett.

This is deliberately lightweight. 6 chapters of mostly fluff.

Thoughts are appreciated.