"Three-oh-two," John announced, wincing as he dabbed his bleeding finger on a cotton pad.

Sherlock was untwisting the lid to the bottle of vitamins and nearly broke the cap. "You've already lost two stone and your glucose still keeps running high."

"It keeps running all over the place," John corrected, "And I'd rather it be high than low. Not likely to get DKA if I check it regularly, but I might die in my sleep if it drops below 40."

John had already woken up once due to hypoglycemia. He had called Sherlock, who quickly fed him some orange juice. That had been a bad night, and John had grimly reminded Sherlock that eventually, his body might be so use to wild sugar levels that there would be no warning.

"Might have to consider a bioimplant," John continued, as he accepted the tablets from Sherlock. "That way I can at least sleep at night. I'll need to look at the research on it though."

"If it's going to save your life—"

"It'll keep me from dying from hypoglycemia, yes," John shook his head as he gagged a little. "Ugh. These vitamins make me feel nauseated."

Since his pancreas was responsible for secreting enzymes that broke down fat, eating fat gave John diarrhea (and, in fact, eating pretty much anything gave John diarrhea), so his absorption of fat-soluble vitamins had been compromised. The enzymes he took by mouth were only of moderate benefit because the stomach acid would denature and deactivate them before they reached the bowel. John was prescribed supplemental vitamins, but since the problem resided in the absorption of these vitamins and not his ingestion of them. all they had managed to do was irritate his digestive tract even further. He was already becoming more prone to bruising, though there was no evidence of frank bleeding yet, and his Vitamin D levels were low despite inhaling tablets full of those things. Sherlock was thoroughly appreciating how lousy it was to have a pancreas that stopped doing its job, and this was not even counting how John was unable to summon the strength to do anything at all.

All the little things behind the scenes that one never thought of until they fall apart.

It was maddening.

"I was thinking," John said to Sherlock as he eyed his toast and peanut butter—the peanut butter was giving him pause because it was heavy in lipids despite being nutritious—"you should probably tell Greg to give you some cases now."

"Who?"

John gave him a look. "Greg. Greg Lestrade?"

"Oh. I could have sworn his name was Gary…"

John rolled his eyes.

Sherlock was already deleting the name. Who the hell cared? "I don't need to put up with boring cases from Lestrade now."

"You've been cooped up here with me for long enough," said the doctor. "There's no reason for both of us to mope around the apartment."

"I'm not moping!"

"You're not doing anything you enjoy. You can't even play your violin because of me."

Of course he could not. He never knew when John needed a nap—and with the poor sleep he had been getting, shallow and barely classifying as a doze, he had taken to sleeping whenever he could keep still at all—which was a poor substitute for a truly good bout of sleep, but better than nothing.

"You need to get out before you go mad," John went on.

Sherlock huffed. "I'm fine."

"Seriously, Sherlock," John leaned back, still not touching his toast or peanut butter, "this isn't good for you, and there's no point in both of us being trapped here. I probably won't be able to help you for a long time. Possibly ever. This isn't something that you can just wait out."

The words made something lodge in Sherlock's throat. Ever. Two months ago, he would have scoffed at the thought. Now, he could actually imagine it. John looked gaunt. He had always been small; his loose jumpers and open jackets often hid how slender he actually was. Now he seemed frail and decrepit, and with ten years added on to him. His cheekbones stood out, shadowed, and the bones of his wrists jutted over wasting muscle. The cancer was supposed to be gone, but it had made its footprint in his body. John should not weigh so little, and it was small wonder that he had no strength to do much more than walk a little around the flat.

Once, Sherlock hated working with people because they always got in the way. Even Lestrade would often bar his path with processing and procedures and reluctant tolerance. John had a way of making Sherlock more efficient, because he could follow Sherlock's thoughts and clear the way for his quirks. But more than that, he was a steadfast ally, a safe post to which Sherlock could always come to when the world around them became too horrid and cold. Solving crimes, cracking puzzles was glorious and thrilling, but with John by his side, Sherlock could fly further than he could ever reach alone, because John was the rest in between, the shelter when lost and stranded, the healing when hurt. Someone would come for Sherlock if he were ever trapped. Someone would haul him up if he ever fell.

John would not be able to do any of that now. And now Sherlock was reluctant to take off, because while he might have been daring, he was not stupid. He knew how many close calls he had. He could never go back to being alone.

He scoffed, before banishing the thoughts, while John's lips turned down into a disapproving frown.

One morning, John asked Sherlock if he could find Harry for him.

"She hasn't been answering any of my calls. She hasn't posted on the blog either. I just want to make sure she's alright."

Sherlock glanced at the time. "Likely passed out, may be hungover but likely still unconscious at this hour."

"Sherlock," John sighed, "Think of this as a case, alright? I'm just asking you to go over to her flat. I can't make it myself. I mean, I probably can, but I don't necessarily want to confront her in person. I just want to make sure she isn't…dead in a ditch somewhere."

"It's too boring."

"Sherlock!"

Ugh, fine! Sherlock reached for his phone.

John is asking after Harriet Watson. -SH

The reply was prompt. She has found herself the daughter of a wealthy entrepreneur. -MH

Bloody tramp. Sherlock looked up. "She's dating some rich brat. She's fine."

"…Mycroft? Really? Was he keeping tabs on her?"

"Mycroft's only talent is to spy on everyone."

"But…what do you mean she's dating…"

"'She has found herself the daughter of a wealthy entrepreneur'," Sherlock enunciated. "I'd ask for pictures but I really cannot care less. Good for her, finding someone who can pay for all her drinking." He waved his hand dismissively. "Are we done? Is your blood glucose at least somewhat normal this time?"

John did not answer. He was staring ahead, sightless and blank.

"John."

"Oh." John blinked rapidly. "Ah, um, I haven't checked. Yet."

Sherlock had yet to reach the limits of his patience, but John barreled past it in the span of one evening to the next. He had managed to maintain relatively good spirits for a while, but some threshold was crossed without warning, and the doctor started being snappish. It started when Sherlock discovered that John had taken to sleeping on the sofa because he was too tired to climb the stairs.

"We should switch rooms," Sherlock offered, since that was the obvious and logical solution to the problem.

"We're not switching rooms," John replied. "I like my room better than yours."

"Why? Mine's bigger."

"I don't like big bedrooms, alright? Not all of us need to live in a mansion to feel good about ourselves."

Sherlock had been rather baffled by this, but his uncertain silence was enough of an argument to snap John out of his odd mood, though not enough for him to agree to switch rooms. "I'm going to decompensate even further," said the doctor. "I'm keeping the upstairs bedroom."

Then came the colleague that had insulted John for being a GP—Dr. Green, his name was. A well-meaning phone call was conducted with failure of normal etiquette as Green joked that John was"not much worse off, considering [he was] not doing much more than measuring blood pressures and referring all his patients to specialists." After the conversation, Sherlock found John in his chair, glaring intently at where bullet holes once were in the wall Sherlock had made with John's Browning.

"It's not what I would have chosen, if I had other options," John explained. "I loved surgery. But that doesn't mean I find general practice shameful somehow. They think general practitioners are the bottom of the class, but what does that mean, anyway? You're so great at taking paper tests. Is that what physicians are about? Multiple choice questions? Sarah sat with me in the ER when I had that pulmonary embolism even though she had patients lined up. The other doctors at the office took on her patients so that she could come in the ambulance with me. What did my surgical colleagues do when I was shot? They never even called. Once I started posting on my blog about detective stories and got famous, oh, that's when they remember that they once had a colleague named John Watson. Sure, you're at the top of the class, but you have the heart of fucking snake. You slither your way to the top and revel in how much better than others you are, when all you were better at was getting high scores on evals and kissing arse. Stalin would have made a brilliant medical doctor, then."

But his mood kept darkening, and he would stare into his tea with a blank, distant stare. It started with him coming downstairs very late in the day; Sherlock knew he had been awake for much longer, but for some reason chose not to get out of bed. Then he turned off his phone, prompting Lestrade and Stamford to call Sherlock instead. When they asked to come to see him, John would turn in to his bedroom for a nap. He could have just been tired, but the timing was too perfect. He stopped reading the medical journal issues, ignoring the mail completely, and he stopped going on his laptop to check his blog.

It all culminated when Molly Hooper showed up with a box of homemade brownies, making Sherlock wonder if at some point she had dissected out her own brain while working in the morgue.

"I know John's probably not going to be able to eat this," she said apologetically, before Sherlock could cut her down to size, "but…I mean, I don't really work with…cancer patients. Except their parts. Or if they're already dead."

Sherlock stared at her and wondered how it was possible for someone who actually cared about the feelings of others to have even less tact than he did.

"So I mean…I don't know if…just in case he can eat these once in a while—"

"No."

"…Oh…" She looked away to search for John sitting at the coffee table, and her eyes took on that glassy look that signaled the coming of tears. "Well…would you like some…Sherlock?"

"Go gain the weight that he's losing," Sherlock snapped, this close to bodily shoving her out of the flat. The thought was abhorrent; Molly Hooper getting as fat as Mycroft while John continued to waste away despite all their attempts. Come to think of it, he was furious at Mycroft too.

Molly's bottom lip quivered. "Oh…" She turned away. "…Okay."

"Molly," John sighed, and his face had a slight green sheen to it, as if he were feeling nauseated, "Look…just…I'm sure Mrs. Hudson would love those brownies."

He rubbed his face when Molly left. "Fuck, I would have let her stay with that box but the smell was making me sick."

"Didn't she also go to medical school?"

"Yeah, but as she sort of mentioned, going to medical school's different from working with someone who has cancer. Or having cancer. Besides, some patients can handle brownies; there were blog posts about marijuana brownies to help with appetite. Just…take it easy on her. She actually cares, unlike certain bloody twats out there."

"She would do us all a favor by caring less."

"Look," John suddenly looked up, "she really doesn't need you to shite on her like this, okay? Heaven fucking knows that even the perfect Sherlock Holmes makes mistakes and occasionally does the opposite of what he intends to do. She wanted to show she cared. So she blundered it, but you know what? I might have done the same, or worse. Far more tactful people have abandoned their loved ones in this situation because they didn't know what to say—Molly could have stayed at Barts instead of coming here and I wouldn't have been able to say a thing. So let it go, alright? Not everyone will get it right all the time, and frankly, I don't give a damn, because at least she's trying, and I really don't have the strength to call her up and apologize for you."

"I was just—"

"You made her cry," John interrupted. "She came to cheer me up and you sent her right back out in tears."

"You were the one who sent her out!"

"Oh my God!" John snapped. "Fine! I sent her out! Then for once in your life, apologize for me! How did I land with such an idiot?!"

That stung, because John meant it. The pain of it was a shock, and the indignation roared up almost on reflex.

Sentiment. See where it gets you?

"Fine," Sherlock bit back. "Then next time, I won't bother helping you!"

He was already by the park when he realized he had left the flat by himself for the first time in weeks. London was covered in slush, and the wind was cold and moist on his face, but the smell of ice penetrated his sinuses and cleared a fog he did had not even known was clouding his mind.

The anger extinguished in an instant, but he stood staring at the dark pines and the peeling planes, unwilling to go back to the stuffy flat. People were commuting up and down the blocks, and he watched—there was a mother of two, there an Asian graduate student, likely from Singapore, a newly-divorced banker, a tourist from Australia. Some walked briskly, while others ambled along. Sherlock stood as still as a statue, feeling as if he would reel once he moved.

Strange, how he seemed to almost forget that beyond the walls of 221B, there remained the rest of the world, still moving along. It felt like walking through the looking glass and into another realm, another London. It felt wrong, to be here without John; he felt adrift, in the sea of couples falling into and out of love, children growing, seniors dying…

Cases. There were still cases. Murders, thefts, mysteries, cropping up even though he had stopped paying attention.

It was odd, being out without John, but at the same time, it felt familiar. He had never spent so much time with John in one sitting. John had been a constant presence, but in that he was always available, not that he was always nearby, demanding attention. In fact, one of the good things about John was that he never demanded attention, even when he probably should. He was independent, capable, and yet helpful because he chose to be. Before his diagnosis, it was not unusual for Sherlock to go for days without seeing John, either because John had been sleeping over with one of his girlfriends, or Sherlock had been out all night on a case too cumbersome to include John. All told, the time they spent apart from each other far outstripped any time they spent with. Hardly surprising that both of them were losing their marbles.

I needed this. Sherlock inhaled. John was right; he should not have kept to the flat for as long as he did. Of course John was right. John is often right, as often about subjects like this as I am about everything else. He considered buying a smoke, but dismissed it; he did not want to expose John to particulates.

Should I take cases? But the thought of those made his heart clench. Though Sherlock solved a fair number of cases without John, he liked knowing John was close at hand should the situation call for it. Besides, what cases could he take? A seven or an eight could distract Sherlock from taking care of John for days. A six or lower is too boring to contemplate. Besides, did he really want to look at dead bodies when John was so close to being one of them?

But this was nice. Out in the streets of London, there were stories everywhere. Sherlock could look his fill before going home to John. The rest of the world may spin on, and whenever Sherlock got tired of John he could seek refuge a few blocks away. No need for cocaine. No need for Lestrade. No need for Mycroft. Just…a breather. And then he could go back, both of them would have calmed down, and while it would not be like before, it would be a step closer.

By 4:30 in the afternoon, it was dark. Sherlock remained out for another hour before he stepped his way back home over the salted concrete. He had not quite forgotten why he left in the first place, but his temper was quiet and his mood subdued. He was not very worried about what he might find, so seeing Mycroft at the sink was like getting dunked in ice water.

"For crying out loud, what are you doing here?"

"John called. You left your cell phone," Mycroft replied without turning around. He had taken off his coat and had his sleeves rolled up to his elbows. Is he actually washing dishes? Sherlock was not sure if he was awake anymore.

"Why did he call you?" Sherlock tried to deduce but came up with nothing.

Mycroft finally turned around. He was washing dishes, to Sherlock's complete bafflement. Grabbing a towel, the elder Holmes dabbed his hands and forearms dry before rolling his sleeves back down.

"Had a good walk?" he asked lightly, his face betraying no emotion.

Sherlock did not dignify that with a response. "Where's John?"

Mycroft gestured vaguely. "Freshening up." He looked at the coffee table absentmindedly, and Sherlock followed his gaze. Huh. There use to be a box of tissues, but now it was missing.

"How long were you here?"

"Long enough." Mycroft retrieved his coat, which was sitting in…ugh, Sherlock's chair. Clearly John neglected to take Sherlock's seat so Mycroft would not contaminate it with his fat derriere. "Since you are returned, I shall take my leave."

He hung the coat over his arm instead of putting it on, and picked up his umbrella, throughout which he did not look at Sherlock again. Sherlock paused to consider if his brother was actually angry with him too, but no, it seemed like Mycroft was just making a point of getting out of the way as soon as possible. The door slammed shut behind him with no more force than usual. Through the window, Sherlock saw Mycroft cross the street to reach the black car parked at the other curb. Sherlock had completely missed it on his way home.

Fat git, he thought vehemently, aghast at his own performance of late. He did not watch the car pull away.

Sherlock's phone was on the kitchen counter. There was a text message from John.

I'm sorry, Sherlock. I didn't mean to imply that I don't appreciate your help. I'm really sorry. Please come back? -JW

Well, that actually explained a lot.

Fuck.

"Sherlock?"

Sherlock turned. John had left the bathroom. His face was newly washed, but his eyes were still swollen and slightly red. Nothing but time could hide that particular evidence.

He had been scared. He had texted. He had realized he had no means to reach me. Then he panicked. He called Mycroft. Mycroft came over. He had cried. Mycroft had stayed with him until I came home. Why had he been so frightened? Did he need me for something? Why tears? John is not that type of man. Was he worried I would not come back? He should know I would come back eventually. I would not have left without my phone, at the very least. Plus, this is my flat. If anyone should leave, he—but he has nowhere to go.

It required no thought to go to John and wrap his arms around that frail body, so the planes of their torsos pressed close and he could feel John's heart beat against his chest. John reached to hug him as well, face buried in his shoulder.

"I'm sorry—"

"Shut up," Sherlock squeezed more tightly. "We never apologize to each other. Do not start."

John huffed, half-laugh and half-sob. "I don't feel like myself. I didn't mean—"

"Then don't try to act like yourself." Sherlock cupped the back of his head. "We'll do an experiment. From now on, you start acting like me, and I like you. I make you tea and you steal my laptop. How does that sound?"

John huffed again, this time more laughter. "I can't really play the violin at three in the morning."

"You can try if you want to." Suddenly, Sherlock longed to teach John. He had never heard of anyone mastering the violin if they tried learning after they turned ten, but the point was hardly to make John as good of a violinist as Sherlock. It was something…enjoyable. A way to share something of himself with John. The violin was Sherlock's most prized possession, other than his own brain. It was unique, and learned to adapt to Sherlock's style as much as Sherlock had adapted to its wood and grain. He could exchange his microscope for another, but he would never exchange his violin. Not for something less than a Strad, anyway.

Even a Strad was not good enough, honestly, because it was not his.

John laughed again. "You wouldn't want to hear me play. It would drive you bonkers. I already drive you bonkers."

"No worse than what I do to you," Sherlock pointed out, but for some reason, John burst into tears.

"I'm sorry," he sobbed, even though Sherlock had just told him not to say that. "I'm a lousy flatmate—I—you shouldn't have to—"

He could not finish. Sherlock was utterly lost. Well, fuck. He never anticipated having to deal with a tearful John himself. What do I do? What do I do what do I do…

"You're not a lousy flatmate at all," he said, feeling awkward. Was this the right thing to say?

John sniffled violently. He pulled back, and seemed to look for tissues. Thin liquid streamed from his nostrils, more tears than snot. Sherlock glanced at the coffee table, but the box of tissues did not magically reappear.

John drew away from him, and before Sherlock could react, he fled to the bathroom, shutting the door. Sherlock heard the sound of the faucet streaming, and then a long silence interrupted by hiccups.

He stared at the door for a long time. He had no idea what to do.