By the time Arthur finally returns, there's only 55 hours left and there's a tea stain spreading across the suede of the sofa cushion. It's shaped a bit like a skull and Merlin shudders as Arthur unpacks three carrier bags of grocery shopping in the kitchen. It's partly from the cold; even in his ridiculous rainbow hat, hiding patchy regrowth, and a huge tartan blanket, Merlin is far from warm. He wonders if this is how skeletons feel.

"Where did you go?" he calls to Arthur. He hears Arthur drop a tin of something and swear. It makes him smile for some reason.

"Work," Arthur replies, stepping into the living room and leaning against the doorframe. He looks tired. "I am incredibly important and earn an awful lot of money, you know."

"I know," says Merlin. "Ties that tasteless don't come cheap."

Arthur looks down at his tie. It's a yellow and blue pinstripe affair that, from a distance, blends into a block of mud-brown. He grimaces.

"Actually, I have Morgana to thank for this one," he counters. "Birthday present, 2009. It's a classic. I think she got me a corduroy one for Christmas."

Merlin sniggers, even though it makes his lungs crackle.

"It looks ridiculous."

Arthur raises an eyebrow.

"You can't talk," he says. "You are wearing a blanket."

Merlin sticks his tongue out, and for the next hour it's small talk and then there's only 54 hours to go and he still hasn't told him.

The next day, when the countdown stands at 44 hours, Arthur takes Merlin out. They don't go far, not only because Merlin doesn't really feel up to it, but because Arthur is a lazy git who won't walk three miles when he could get a bus for two. They end up at the park,

"Gwen said you had something you wanted to tell me," says Arthur, suddenly. Merlin's heart thuds. He knows that Gwen is never anything but well-meaning, but he does wish she'd stay out of things sometimes. He's reminded of the time she attempted to break his involuntary spell of celibacy by making a profile for him on a gay dating website. He still hasn't quite forgiven her for his subsequent nightmarish date with Declan.

He forces a small smile, cold lips falsely upturned.

"Yeah," he says. "I wanted to tell you that you can have my Xbox if I snuff it in a few days."

Arthur snorts.

"I don't think that's it," he dismisses. Merlin looks at him. He's not getting out of this that easily, he can tell.

He sighs. He can think of a plausible lie. He's good at that.

"I just wanted to say," he says. "That I'm scared."

And it's not a lie, it's really not. He's fucking terrified. He's facing his own mortality dead on, looking it square in the eye, and he doesn't like what he sees. He thinks he's entitled to feel a little fear.

Arthur's face softens. Merlin feels momentarily guilty at the half deception, but he can't tell Arthur. He just can't. There's only 40 hours left. If Merlin tells him now, the best case scenario is forty hours of Arthur feeling the same. The worst case scenario is forty hours of stretched out solitude, and sorry if Merlin doesn't fancy facing that.

"You're allowed to be, you know," says Arthur. "I mean, I'm incredibly brave – nay, fearless – and I think that even I'd balk a bit at having to go through what you are. You're dealing with it better than most people. Don't beat yourself up about feeling a bit shitty about it all. You've earnt it, you know?"

Merlin nods.

He wants to tell Arthur, of course, that he's the best friend he's ever had, that he wants that to be the gateway to something more, because he likes the dimples formed by smiling and the sweep of blonde hair at the nape of his neck and the flush of his ears when he's embarrassed.

"I'm scared," he repeats, and it's not a lie.

Lancelot furrows his brow disapprovingly and pours Merlin another cup of tea from the fancy teapot that he only ever uses on special occasions. Merlin leans back into the unfamiliar sofa and covers his face with his hands.

"Come on, Lance," he groans. "I've had more pressing matters to deal with. Such as my potentially impending death."

Lance wrinkles his nose and pushes the cup of tea closer towards Merlin across the coffee table.

"Yes, I can see you're busy," he says. "Busy ensuring that what could be – won't be, but could be – your last few days are as miserable as possible."

Merlin sniffs.

"I'm not," he retorts lamely.

"Just put Arthur out of his fucking misery, Merlin," Lance sighs. The swearword rolls too easily off his tongue for comfort, doesn't sound as foreign as it usually does from Lance's lips.

Merlin takes this as an omen.

"I don't know what you mean," he says.

Lance raises an eyebrow.

"36 hours, Merlin," he says. "Two nights and a day. You have all the time in the world after the operation – you do, you do – but don't you want to get it out of the way before then?"

"No," says Merlin, stubbornly. At Lance's cocked eyebrow, he elaborates. "There's no point," he continues. "You can't accomplish anything meaningful in 36 hours. You can't achieve anything worthwhile. Rome wasn't built in a day."

"No, but the world was built in seven."

"I'm an atheist."

"You're either missing the point spectacularly," sighs Lance, cradling his own cup of tea. "Or you're being deliberately obtuse. 36 hours is more than some people get, Merlin. Use it wisely, for God's sake."

"I'll think about it," Merlin mutters, and he doesn't for another three hours.

His sleep that night is fitful. He's in Arthur's bed. Arthur isn't, having valiantly given up his bed for the sofa when he decided that Merlin was going to stay with him. He dreams sporadically of cobwebs and spiders and bones and in between dreaming he can hear Arthur knocking about downstairs and he's too tired to go downstairs and tell Arthur yes, and then there's 27 hours.

"It's going to be fine, right?" Morgana asks, chewing her lip, leaving a tiny, almost imperceptible smudge of crimson on her front tooth. Merlin grips her hand a little tighter.

"Yeah," he says. He looks across at Arthur, engrossed in a conversation with Gwen. "Think Arthur would have a word with the powers that be if it weren't."

Morgana smiles.

"He would," she agrees. She looks at Arthur for a second. "He'd probably win, and all."

"If anyone could, it's Arthur," concedes Merlin. He takes another sip of water and draws his cardigan around him more tightly. He's not cold or uncomfortable. It's a good feeling. He'd forgotten it. He looks at Arthur. He's fully absorbed in his discussion with Gwen, gesticulating wildly and talking animatedly. Gwen listens, amused. Arthur's always been like that. He doesn't do things by halves. Merlin's never appreciated it more than he has these past few months.

He looks at Morgana. She's watching him, a small smile playing on her lips.

"Tell him," she says, softly. Merlin sighs.

"Not you, too."

"Everyone," she agrees.

"Can we talk about something else?" Merlin groans. Morgana raises an eyebrow.

"Looking forward to your risky surgery tomorrow?" she asks, bluntly.

Merlin supposes he asked for it.

"What do you want to do with your last twelve hours of freedom?" Arthur asks. Merlin looks up, bleary-eyed, from his nap.

"Sleep," he suggests. Arthur scoffs.

"Merlin, there'll be plenty of time for that on the operating table," he says. "I forbid it. Now, get up. Put on your best little black dress. We're going outside."

Merlin moans.

"I can't go out now, Arthur," he says. "I feel like death. It's 8pm. Can't I just sleep?"

Arthur raises an eyebrow.

"Firstly, Merlin," he begins. "I said 'going outside', not 'going out'. There is a marked difference. Secondly, no. No, you cannot. Life is for living, Merlin. You're going to dream it all away."

"There's not much of it left to dream away," Merlin mutters.

"The average life expectancy of a male in the UK is 79," Arthur counters. "That gives you another 53 years. That's a fair old while."

Merlin sighs.

"Pass me my scarf and coat, then," he acquiesces.

The garden is cold and frosty and Merlin marvels at the way he can see his own breath, little plumes of white mist in the air, heavy with the threat of a dewy dawn. He wonders if the breaths he exhales will stay in the atmosphere after he's gone, little puffs of gas amongst the clouds.

Arthur looks at him strangely.

"What are you doing?" he asks.

"Breathing," answers Merlin. "While I still know how."

Arthur huffs out a small laugh.

"You're a funny one, Merlin Emrys," he says.

He looks down at his hands, clad in an old pair of Merlin's fingerless gloves. His fingertips are white. Merlin looks down at his own hands, soft and warm in a pair of Arthur's ski gloves, and guilt washes over him. He sighs.

"Give me your hands, you moron," he says. Arthur glares at him.

"I am not a moron," he says, making no move to offer Merlin his hands. "I just didn't want to be the douchebag who bagsied the decent pair of gloves and left my poor cancer-stricken friend to freeze."

"Well, you did drag me out here," Merlin counters, taking Arthur's hands in his own, enveloping them in the thick fabric. Arthur sticks his tongue out. Merlin shakes his head and rubs Arthur's hands between his.

"Thank you," says Arthur. His voice is small and the garden is dark and there's 11 hours left.

"It's OK," Merlin says. And it really is. He can't give much, hasn't got much left to offer, but he can give this. Warmth. It's a fundamental thing and it's human. It's a connection.

Arthur's cheeks are pink with the cold. Merlin doesn't really know what he's doing but there's 10 hours and 58 minutes left and then his hands are on Arthur's cheeks because he wants to warm them up, and then Arthur shivers and Merlin wonders if it's from the cold, so he moves closer to Arthur, offering bodyheat, and then he thinks that Arthur's lips look cold too and he thinks that that's not right, so he presses his lips to Arthur's and yes, that's warmer. And there are still cobwebs in the clouds and skeletons underground and a stopped clock in the spare bedroom, but Arthur's here and he's solid and he wants Merlin and Merlin wants him and it's everything.

It only lasts a few seconds, a dry press of lips, but it's a few seconds closer to the deadline and when Arthur makes a little noise in the back of his throat, Merlin thinks he could spend the next 10 hours just doing this, just being warm, and he pulls back slightly to tell Arthur that he's found a way to spend his remaining time, but Arthur's hands are on the back of Merlin's neck and suddenly he doesn't want to pull away any more, thinks Arthur knows what he wants, and so he doesn't.

He knew 62 hours ago, he thinks. He was so cold for 62 hours. He didn't have to be.

Arthur moves his hands slowly from Merlin's neck, places them on Merlin's cheeks and pulls away, meeting Merlin's eye.

"You're sure?" he asks. Merlin nods. Arthur inhales a sharp little breath. "Fuck," he says. "You know I've wanted this for ages, right?" Merlin nods, slightly embarrassed. "And you do want this?" Arthur asks again. "You're not just, you know, humouring me?"

"No, I do want it," he replies, mouth dry. "I mean, obviously it's not going to get any further than this tonight because I'm a bag of bones and I have an operation tomorrow and you know, this is quite nice actually, it's not like we have to shag like rabbits to make each other happy, and - "

Arthur rolls his eyes and kisses him briefly.

"Shut up, Merlin," he mumbles, and Merlin does.

For 10 hours, 10 hours of bad television and tea and warmth, he does.