A/N: I can't believe myself. But I watched an episode of Castle, and then my brain wouldn't shut up until I wrote this Castle-inspired Sherlock story. It's totally ridiculous, but what can I say? It was write this or go even more insane because of school. And apparently I can't come up with my own storylines anymore so I have to steal them from other tv shows and turn them into Sherlocky stuff. So I own almost literally nothing about this. Except my mistakes, since this is un-beta-ed. Enjoy; I certainly did!

Castle to Alexis: "Sweetie, everything you do matters. Every moment, every decision you make, it affects the people around you, it changes the world, in a million imperceptible ways. No matter what your reality, you can make it better." - The Time of Our Lives (Castle, s7, e6)

CHAPTER ONE: Going to Regret This...

After finding toes in the bathtub for the sixth time that week, John Watson stormed out into the sitting room, with the serious desire to pick a bone with a certain someone.

Obviously, that someone was his insufferable detective.

"Sherlock," John snapped, the colander of severed body parts - cradled in a towel just in case they had been steeped in toxins or something - clutched gingerly in his hands. "Do you want to tell me what the meaning of this is? Again?"

"I told you. Experiment." Sherlock didn't even look up from his microscope. "Put it back."

"I'd like to take a shower."

"It doesn't take up much space."

"It's a colander of severed toes! I am not showering with them!"

Sherlock shrugged, but barely. Clearly whatever was under the microscope was far more interesting than this conversation. "They can't be moved. Now if you'd replace them before the entire experiment is ruined-"

"Dammit, Sherlock, I don't bloody care about your experiment! Can't you see how bizarre and inconsiderate you're being? Normal people don't put toes in the bathtub!"

Sherlock's brow furrowed faintly. "Strictly speaking, they aren't in the tub. The colander is..."

"Oh, you know what I mean. This is the sixth time this week I've stumbled across a pile of toes, Sherlock, and I've had it! Either move them elsewhere, or you just might find me moving elsewhere!"

Sherlock had the audacity to chuckle. John had indeed said such things before, but he wasn't so sure he was bluffing this time. Work had been maddening lately, and this was the last straw.

"I wish you would take me seriously," he muttered, slamming the colander onto the kitchen counter and starting to storm off for a sulk. "Then maybe you'd be a bit easier to live with."

"What?" John looked back and saw, to his surprise, the briefest flicker of hurt in Sherlock's eyes. He was too surprised (and still too miffed, to be honest) to feel guilty, though.

"I said, I wish you were easier to live with."

The hurt was quickly masked by a facade of derision and falsified amusement. "You'd miss me if I were gone."

"No, I don't know that I would. I'd probably be a successful doctor with a steady job without you, and I'd sure as heck have a more peaceful life. You're the one who takes me for granted, I think you'd be the one to miss me if I were gone."

With that, he turned and stomped up the stairs to his room, indulging in a good door slam. He could feel guilty about yelling at Sherlock in the morning; for now, he just wanted to sleep. Especially since a shower was now the last thing he wanted at the moment. Who knew what sort of toe residue was in that tub?

He yawned and lay down, stretching out languorously. Within minutes, he was drifting off to sleep. Thus, he did not see the figure slip inside the room via the window, stealthily approach the bed, then after a moment depart the way it had come.

The next morning, John got up and stepped into the shower first thing. It took him nearly three minutes of standing under the warm spray before he remembered the toe issue from the previous night. Grimacing, he rushed through shampooing and leaped out of the tub as quickly as he could without killing himself, then toweled off his feet gingerly. He spent the next few minutes trying desperately not to think about all the possible infections he could get.

When he was dressed and hopefully decontaminated enough, he stepped out into the kitchen, where Sherlock stood leaning against the counter. A cup of coffee was in his hand, and he looked as if he hadn't slept. John stepped over to the cabinet and poured himself a coffee.

Sherlock carefully avoided his eyes the entire time, and John winced. He had clearly hurt Sherlock's feelings, something he was unused to doing. It wasn't often someone was able to get under the detective's skin, and John was still in a state of surprise that he was able to do so now. Also that his comment from the night before had even affected Sherlock.

He opened his mouth, but if an apology had been about to come out, he never found out. Sherlock's phone rang at that precise moment, and John snapped his mouth shut again, sighing and taking another sip of coffee.

"Sherlock Holmes. Where? Well, obviously I'm coming, do you think I would ask that if I were planning on staying home? Yes, good for you, I'll be there soon."

He hung up and glanced at John, calculatingly, as if gauging where they stood with one another.

"Case?" John asked, trying to finish the coffee before they left. Of course he was coming, one fight wasn't going to change that.

Sherlock nodded. "Homicide in the east end. Coming?"

"Why not?" John shrugged and tried not to look too eager. It was his day off anyway, and a homicide sounded like a welcome break from dealing with flu season.

One slightly tense cab ride later, he and Sherlock arrived at the crime scene, which consisted of a cordoned-off section of street alongside a not-so-reputable-looking line of shops, half of which appeared to be abandoned. There was a body, sprawled inelegantly across the kerb, a small bloodstain on the pavement beneath it.

"Well?" Sherlock asked, snapping on gloves and stepped past Lestrade, who stood near the police tape, waiting for them.

"Victim's a middle-aged bloke, no name yet. A single gunshot to the chest, no signs of a struggle otherwise. There's some white powder on his hands, dunno if it's drugs or not yet. We'll know when we get him to the-"

"Of course it's not drugs," Sherlock chuckled, kneeling beside the victim. "It's powdered sugar. Even a blind man could see that, but then you aren't blind so I wouldn't expect you to realize."

He ignored Lestrade's sputtering and inspected the body. John stood to the side still, waiting for Sherlock to cue him. He wasn't sure how to play this yet, since Sherlock was apparently still upset.

Sherlock's brow furrowed, and he shifted his weight so he was closer to the victim's feet. He reached out and pulled a bit of dirt off the bottom of his shoes, crumbled the clods between his fingers for a moment, then sniffed them gingerly.

"This dried mud is from the west end. You need to show his picture around there. Perhaps someone will be able to identify him."

But John never heard Lestrade's reply, because at that moment, he staggered, going lightheaded. Before he could react to this sudden vertigo, the pavement rushed up to meet him, and everything went black.

John's eyes opened to find himself stumbling. He caught himself at the last minute, grabbing a lamppost for support and righting himself.

Okay… What just happened?

He looked around and found, to his surprise, that he was back at the end of the street. The crime scene, bustling with investigators, was several hundred yards away.

I'm losing it, he thought, giving his head a shake. Maybe those severed toes gave me an infection in my brain.

Pushing away worries about more serious and feasible explanations - a brain tumor, dementia, shut up Watson, do this later - he headed back over to the police tape and ducked underneath it.

"Oi," Sally Donovan called as she climbed out of a car. She hurried over and cut him off before he was even able to stand up straight again on the other side of the tape. "What do you think you're doing?"

He frowned. Even she wasn't usually this hostile, at least not to him. "I'm here to help Sherlock, what do you think I'm here for?"

She raised her eyebrows. "Holmes?" She looked over her shoulder and her eyes darkened. "Greg, could you come here?"

John tried to get past her, really confused now. Why was she being so difficult? She stopped him, however, looking at him with alarm and... There was no recognition whatsoever.

Lestrade approached, frowning. "What is it?"

"First of all, what is the freak doing here? You know what I said about this."

Lestrade shifted, looking strangely sheepish. "You said we'd need all the help we could get. So I texted him-"

It was that moment that John managed to get a look around Donovan at the crime scene, where he spotted Sherlock, crouched by the body, gazing intently at the chest where the powdered sugar was. He didn't appear to have noticed the exchange between Donovan and Lestrade yet.

Donovan sighed. "This is the third time this month, Greg, I can't have this. You know he's not welcome here. I don't need this insubordination."

"Sally, you know, he could help-"

"Don't 'Sally' me, Greg. Remember who the DI here is."

John watched this exchange, frowning. "He is."

Donovan laughed softly, though Greg turned a puzzled look onto John. "Who's this?"

Before John could reply, Sally spoke. "I don't know. He claims to know Holmes, but last I checked, the freak didn't have friends…"

This time, Sherlock, apparently having heard his name, looked up towards them. His gaze landed on John immediately, and his brow furrowed as he clearly scanned and deduced him. It was strange to be at the receiving end of that stare once again, the stare Sherlock usually reserved for people he was only first meeting.

What the bloody hell was going on here?

"Who's this?" Sherlock asked, standing in a single, swift motion.

"What are you talking about?" John scoffed, finally mustering the ability to speak again, having been struck rather dumb by the inexplicable events unfolding before him. "It's me."

"You know him?" Lestrade and Donovan asked Sherlock simultaneously, their expressions identically perplexed. John didn't blame them; he was feeling the same way.

Sherlock just gave John that look again. John could see the deductions whirling in his eyes, as if his friend was seemingly attempting to recall where he would have met John. Then, something shifted in his expression, and Sherlock squared his shoulders and looked John in the eye.

"I've never seen this man before in my life."

I don't know when I'll get to update this, because the end of the semester is nigh... However, I will never abandon it. I'm legit sitting here giggling about what I have planned, so there will be following chapters, I just can't promise they'll be done soon. Before the new year, let's go with that! :)