AN: GEN, one-shot. I don't own anything you recognize. Also, the usual disclaimers for medical and historical inaccuracies apply (that being – they're probably everywhere in this). Warnings for described illness.

The fever seems to come from nowhere, although, if Merlin were honest with himself, it probably started days before Arthur was so far gone that he'd been unable to keep it to himself any longer. A few nights into it as he sits at his prince's bedside he thinks back on the days before the fever, and thinks that maybe Arthur had seemed paler, or that maybe he had faltered during training, or maybe he hadn't been eating as well, but he cannot be sure. As it is, it isn't until he bustles into Arthur's chambers one morning, carrying the customary tray of breakfast, and discovers that Arthur will not be woken – that Arthur's pale cheeks are covered in a sheen of sweat, that Arthur is shaking, shivering, despite the thick, rich quilt covering him – that they find out that Arthur is ill.

Merlin immediately sends for Gaius, and returns to the prince's bedside, using his handkerchief to wipe away some of the sweat, murmuring soft words of comfort to the other boy, who only blinks up at him drowsily and miserably.

Gaius arrives a few minutes later, armed with a selection of tonics and herbs, and immediately sets to examining the prince. He declares the fever worrying, but not inherently dangerous, but when he rests his ear on the prince's chest his forehead deepens into a concerned frown before he forces his features into a neutral expression. Merlin just looks on worriedly, until Gaius shakes his head and concedes, "I think I hear the start of a rattle."

Sure enough, a few days later what was once just a hint is painfully apparent, and the prince struggles for breath all day and all night long, only getting the barest bits of respite from Gaius's tonics and treatments. The fever builds with the rattle as the sickness seeps into the prince's chest. Delirium takes hold, and the prince either refuses or brings back up the meagre amounts of broth that Gaius or Merlin or any one of a variety of other attending servants tries to get into him, and as the days go by his strength wanes drastically, and his once lean, but muscled figure seems to shrink before their eyes.

The prince alternates between clumsily pushing at his covers with arms weighted by sleep and delirium, and shivering so hard that Merlin is certain that he, himself, can feel it his bones. Sometimes he stares at Merlin, or Gaius, or whoever is tending to him, through illness-dulled eyes, his eyelids dropping slowly, and then just as lethargically lifting again. Sometimes he says things that really make no sense at all, yelling or mumbling about animals or creatures or fire or mountains or sweet cakes or trees or sorcery. Merlin hardly leaves his prince's side, ever the faithful servant in his master's time of need, and as such he is privy to most of these ramblings. He never pays them much mind, but makes sure to nod or voice his agreement wherever he deems appropriate, but always to gently remind Arthur that he is safe, that he is well taken care of and that nothing can harm him whenever Arthur seems to be working himself into a panic.

The cough is painful to listen to, so much so that Merlin cannot imagine what it must be to have to actually endure it. Yet, there is nothing he can do to help his master but hold out handkerchiefs for him as he coughs and coughs and spits up frightening looking substances that are run with blood, and hold his hand while Gaius subjects him to all manner of pungent steam baths and treatments to try to clear his lungs.

Sometimes Morgana will come to sit with him, holding his pale hand in hers, murmuring softly to him of knights and grand castles and a sweet, young, blond boy-child who she wished she had gotten to know better in the years past. Merlin makes sure to retreat out of sight at these times, keeping a respectful distance but still within earshot should the prince make even the slightest sound of distress.

The king often visits later at night, when all unavoidable affairs have been dealt with. Sometimes he will request that Merlin leave them entirely, but as the days go on he seems to accept Merlin's presence in the shadows of the room, silently respectful, but still available to jump quickly in should the prince show increased signs of distress, or make the pained little noise that Merlin has come to recognize as warning for agonizing bouts of sickness, despite the prince not having eaten anything, that leave the boy breathless and teary and exhausted.

The first few days that Merlin is allowed to stay the king sits in silence, sometimes stroking the prince's forehead, sometimes holding his hand, sometimes brushing away his feverish tears, but as the days go on he starts to talk to his son. Sometimes he apologizes – for the duties he has imposed upon his boy, for the stresses he has dealt his only child, for the distance between them, for the pain and the loneliness of the life of the sole heir to a kingdom. Other times he tells his son stories of Arthur's childhood: of things the king remembers fondly, but also of things that obviously pain him to think on – these he apologizes for profusely, gripping his son's pale hand tightly in his own larger ones. It is during these moments that Merlin learns more about Arthur's childhood than he has ever learned before.

They all settle into a sort of routine, and the days pass, and with them the fever builds, and the look in Gaius's eyes grows increasingly grim. Every day he has a variety of tonics that they carefully coax Arthur to drink, but Arthur brings most of them back up again, and as the days go on Merlin notices that they change from common draughts he recognizes to ones he thinks he has seen in Gaius's more frequently used books to ones he doesn't recognize at all. He tries to reassure himself that this does not mean that Gaius is getting desperate, that it doesn't mean that the tonics aren't working. He settles for trying to convince the incoherent prince that everything really will be alright. Arthur makes no response, so Merlin tells himself that the prince is confident that he'll recover – tells himself that confidence is something Arthur will never lack.

One day, late in the evening Merlin is sitting in the chair beside Arthur's bed, watching his pale face intently. The prince's cheeks are sunken and his eyes look bruised. His hair is curled with sweat, and he whimpers sporadically, to which Merlin will immediately respond with quiet shushes and whispers of encouragement, telling the prince not to fret, that he will soon be well, that everything will be fine. The door opens, and as the king steps quietly into the room Merlin immediately rises from his chair, but as he turns to make his way to his usual corner, a raspy voice freezes him in his tracks and he whips his head back around.

"Merlin… Mer….Merlin…" Merlin has to lean close to the prince to hear the breathy words. Arthur gives him a lopsided smile, and Merlin returns it tentatively, all too aware of Arthur's pallor, his frailty, the fever, as well as the king's intimidating presence so nearby. "Merlin?" Arthur repeats, and this time Merlin responds.

"Yes, sire?"

"Are… are we friends, Merlin?" The prince's blue eyes are wide and rimmed red and fever-bright, and maybe a little bit desperate.

In any other circumstance Merlin would have said yes, or more likely made some sarcastic quip about what a supercilious prat the prince is, but the king is right there, and Arthur is so very ill, and he cannot find the words.

"Sire…" It quickly becomes apparent, however, that this was a very bad response to have made, because Arthur's face crumples and he turns away from Merlin, curling in on himself tightly and pitifully. His shivering escalates into shaking, and he is unable to contain the wretched sobs that tear through the slim frame that has been so weakened by illness. Merlin reaches out a tentative hand and gently places it on the quivering shoulder. "Sire…"

"No."

A frown creases Merlin's brow, but he leaves his hand where it is, wishing he could will health back into the now sparse frame. "Sire…" And again he pauses, unsure what to say, desperate for the right words for the situation, but unable to find them.

"I… I thought," Arthur then says between sobs, "that we might… that we might be… might be friends." Merlin is so shocked by the utter desolation in the prince's tone and the unexpected coherency of his words that he is rendered completely speechless, and after a moment wordlessly starts to rub small circles on the boy's back, his heart breaking, but the prince is not done: "I… I've never had… had a friend before. And I thought… but… but now… I don't…" And with that, Arthur shatters Merlin's heart entirely."

Merlin can't help but turn panicked eyes toward the king, who is hovering silently at the foot of the bed, but Uther's face remains impassive. He makes no indication that he has noticed what Merlin is sure is a gross crossing of class boundaries. So, Merlin throws caution to the wind, and looks back at his prince, running a hand gently over the feverish brow, gripping the frail hand tightly. "You do, sire. We're friends, sire. You're my friend. I'm your friend. I'm your friend, sire." He finds that he's crying, without even having realized it. "Me, sire. I'm your friend." He isn't sure the prince has heard him - isn't even sure the prince is aware of him beyond the delirium, but he answers with conviction and gently thumbs away the other boy's tears, paying no mind to his own.

That night the fever breaks.