One thing John Watson learned was that when a case got going, really got going, there was no time for food, or sleep, or anything that a normal person (meaning someone who was not Sherlock Holmes) would consider necessary to maintain a healthy lifestyle. If he was lucky, he managed to snatch a few bites of something here and there, maybe even an entire sandwich while on the way to somewhere. And as for sleep... Well, that was pretty much a non-issue. It often seemed that no sooner would he lay down than either Sherlock would be shaking him awake shouting nonsense about pencil shavings or some other triviality that John's exhausted brain couldn't hope to understand, or his alarm would go off and he'd have to rush to get ready to go to work at the surgery.

Sherlock, despite being a genius, didn't seem to grasp the need of a steady income or concept of ongoing employment. As a result, time after time, John found himself justifying his absences or promising to run Sherlock's errands when he got back or during his lunch break. He kept telling himself that he'd have a proper lie down tomorrow. Tomorrow he'd not only eat, but manage to eat three well balanced meals. Tomorrow.

But tomorrow never came. Lestrade seemed to have a never ending string of cases for them to help with. John could, of course, have begged off, but any thoughts of doing so were fleeting at best; the life he was leading might be exhausting, but it was exhilarating and he wouldn't change it for the world.

He did, however, need to stay awake for it. Something that was easier said than done. Caffeine only went so far and John discovered that an overabundance of coffee tended to cause the tremors in his left hand to worsen, making it necessary to keep his hand fisted and shoved into his pocket more often than he'd have cared to.

The answer came to him one day as he was filling in for a shift at the surgery. He could barely keep his eyes open and he knew if he didn't do something he was going to fall asleep right in the middle of diagnosing one of his patients. Then, there it was. Staring at him. A started bottle of methylphenidate, otherwise known as MPH, that had been inadvertently left behind by a patient after getting a change to their prescription. Under the brand name Ritalin it was most often prescribed to treat attention-deficit/hyperactivity disorder or attention deficit disorder in children, but it was known to have a stimulant effect on those unaffected by those disorders.

There were procedures John should have followed regarding the abandoned pills, and disregarding them was completely asinine, but how could he look such a gift horse in the mouth?

After much consideration, and another two yawns, John decided that while it would definitely not be a good idea to take such a medicine in the long run, once in a while, if the situation was grave enough, someone with proper medical knowledge like himself could take advantage of its properties without any harm. All he was going to do was take a pill here and there, on days like this one when he was not only sleep deprived but starving, and his brain was too muddled to function. It wasn't as if he was going to abuse them. They would just help him function and no one would be any wiser.

Or so he managed to convinced himself.

Three weeks later he was only halfway through the tablets and he'd never felt more alive. They'd solved another case, well, Sherlock had, but John had helped (Sherlock did need someone to lecture to after all) and even Sergeant Donovan had seemed to be grudgingly admiring about that. He'd even managed a date with Sarah, one that Sherlock had, by some miracle, not interfered with in any way whatsoever.

John bounded up the stairs to the flat after a long day at work, pausing in the doorway when he spotted Sherlock throwing knives at a steak that had been pinned up on the wall.

"Sherlock? What are you," he began before cutting himself off, realizing how Sherlock would respond to such an obvious query. "No, a better question would be why are you doing that? Actually, you know what? Never mind." There were some things he was simply better off not knowing, and how Sherlock had acquired such a diverse collection of knives and exactly what he was hoping to accomplish by hurling them into an innocent cut of beef definitely fitted into that category.

Instead of dwelling on Sherlock's actions he decided to put his time and energy to good use and clean up some of the detritus that had accumulated throughout the flat while they had been focusing all their attention on recent cases and the trivialities of day to day life. Ignoring the occasional thwack, he began picking up around the flat. Takeaway menus, last week's receipts from Tesco, plates from who knew when covered with mould in various stages of growth and a desiccated piece of what he sincerely hoped was an old sausage all went into the bin.

After that John attacked the kitchen, washing anything that didn't seem part of an active experiment. The dried out test tube? Cleaned. The plastic container that look liked it had something moving inside? Left alone. John tried hard not to think about what exactly made up the layers of dried, crusty sediment on the sink.

"John?" Sherlock's tone indicated it wasn't the first time he'd called out, trying to attract John's attention.

John stopped cleaning and turned towards him, confused. "Yes, Sherlock?"

"This has to stop." Sherlock had paused, standing neither in the kitchen nor sitting room, hands behind his back. He had an odd look on his face, one John hadn't seen before.

"Sorry?"

"Your recent use of pharmaceutical aids. It simply will not do."

Oh.

John carefully schooled his face to show no reaction to Sherlock's words whatsoever. "I'm sure I have no idea what you are talking about."

Sherlock narrowed his eyes and John recognized the look being directed at him as one of disdain and disappointment. He realized he had seen it before, but only when Sherlock was near Anderson or one of the others that had been relegated into that category of people who did not have the intellect or common sense to understand the significance of minutiae in solving crimes. "Interesting," he replied, "And yet, I am rather sure you do."

"Is this because I cleaned up around the place? Even you have to admit it was getting hard to walk around without having to watch where you step." To have something to do with his hands John began drying his hands on an oddly coloured towel that had been lying on the floor since Sherlock had thrown it there in a fit of pique the day before.

"Must I really list off every detail that has led me to that conclusion? Why today alone, you awoke a full hour before your alarm; walked to work, spent the last eight hours on your feet seeing patients, skipping lunch I may add, and then walked home, making a detour to post a letter. Once here, instead of immediately bringing up the subject of dinner as you are wont to do, you began to clean with a sense of purpose and euphoric zeal that is quite unlike you."

"So, according to your brilliant deductive reasoning, since I am in a good mood and happen to have a bit of energy I must be a drug addict?"

"Oh, don't be obtuse. I in no way implied that you were addicted," Sherlock huffed.

"No, but you certainly implied that I have taken drugs. Illegal drugs. Have you forgotten I am a doctor?"

Sherlock scowled. "It is your very status as a doctor that makes the fact you've taken drugs all the more likely as it provides easy access to an unlimited supply of whatever you wish, although, current indicators point to something more complex than a simple stimulant."

John tossed the towel into the sink and crossed his arms, tucking his traitorous, trembling hand away from his friend's prying eyes and leant against the table, looking up at Sherlock. "Even if you were right in your assumptions-"

"I never assume-"

John waved away Sherlock's protest. "As I was saying, even if what you were suggesting was correct, why does it matter to you?" John knew he was raising his voice, that his anger was probably confirming Sherlock's suspicions, but it helped cover the pounding of his heart. "What difference would it possibly make in your life?"

"One's reflexes and mental prowess can be affected by drugs. While I am not reliant upon your assistance, I have," Sherlock cleared his throat, "found it useful at times to have you accompanying me. Someone to listen when I talk aloud. Someone to have my back if things were to turn dangerous. When one is under a chemical influence their actions can no longer be accurately predicted: currently I cannot anticipate what you may say or do at any given time. To be quite frank, John, you're useless to me like this."

"I'm useless? I'm useless now? Because of drugs. Really? Well, Sherlock, I have to ask you, what would I find if I searched this flat? I'm not Lestrade or his band of merry men on their pretend drugs bust. I know you. I know this flat."

"As I'm sure you remember me telling Lestrade, I am clean. The same, however, cannot be said for you."

"Sherlock," John began, but he stopped himself from continuing, not wanting to get angry, but knowing what else to say.

Spinning around, his robe flying behind him, Sherlock went to remove the steak from the wall. Keeping his back to John as he worked he said, "I do realize that this is partly my fault-"

"What? No."

"Let me finish," he said calmly. "I have been told I can difficult to get along with at times, doubly so when focusing on a case. And while it is true that I am quite capable of going for days without significant amounts of food or sleep without detriment, I do realize that such abilities are not the norm for the average person. Or even for the..." Sherlock gave John a quick glance over his shoulder before gathering up the knives, "the above average person."

John couldn't help but smile slightly at the unexpected compliment. Above average, coming from Sherlock, was on par with receiving a knighthood or the Victoria Cross.

"A reminder of that, now again, would not be remiss." Sherlock walked past John, dropping the knives in the sink and began wrapping the steak in on of the newspapers John had just collected into a neat pile.

"That's today's newspaper," John commented, dryly.

"Yes, and I've already read it. Boring stuff." Sherlock shoved the steak into the fridge between some beetles and the milk.

"I hadn't read it yet."

"Then you should thank me for saving you the effort." Sherlock took off his robe, wadded it up and threw it on the chair. "I'm bored. Let's go out," he said, grabbing his coat and scarf.

"Yes, let's." John reached into his pocket and pulled out the bottle of pills, staring at it with a sigh.

"Are you coming?" Sherlock called from the hall.

"Yes, yes. Coming," John said, tossing the bottle in the bin as he headed quickly to the door, taking his place a step behind Sherlock, guarding his back.