A/N: I recently watched an episode of Castle where this same scenario occurred, and I couldn't help but switch the characters in my mind and wonder how the Sherlock cast would handle this... it's choppy at first to set the stage for the rest of the story. Yes, I admit that this will turn into a bit of a Sherlolly in the end. Sorry, but I'm really not sorry haha!

Disclaimer: I do not own Sherlock. Or Castle for that matter.

Just One Wrong Step

Chapter 1

"I didn't call you," Detective Inspector Lestrade said to his consulting detective, blocking the entry from the sidewalk to the abandoned flat they had just got a lead on.

"But you need me," Sherlock responded simply.

"Wait, how did you know that this was where…" John began while standing behind the tall head of curls, but Sherlock just gave him a knowing, sideways glance. "Right, stupid question," he finished for himself.

"I may need you later," Lestrade admitted with a slight groan. "But right now, it's not such a good idea. This guy was a bomber, so we're organizing a sweep."

"Unnecessary," Sherlock said as he tried to move through Lestrade.

"How can you be so sure?" Lestrade inquired, squaring his shoulders as to continue blocking Sherlock's entry. Sherlock rolled his eyes and gave an exasperated sigh.

"Do you really need me to spell it out for you?" he asked, shoving his hands into his coat pockets.

"Considering I would be the one held responsible for the consequences of your actions, yes." He relaxed slightly, fully anticipating for Sherlock to take advantage of the opportunity to show off his perceptive abilities in a highly exaggerated matter, but of course, Sherlock already guessed that that's where Lestrade's train of thought was going and was expecting the loosening of his physical stance. This gave Sherlock the opportunity to use his own stature to barrel his way through the doorway, John trotting behind him.

"I'll sign a waiver," Sherlock called backwards sarcastically.

"I, uh…" John was mumbling. "I don't know if coming in uninvited to a bomber's flat is really a good idea, Sherlock.

"Oh, come on. Where's your sense of adventure?"

"I must have left it in Afghanistan with some other bombers I once knew," he answered sullenly. Sherlock ignored this, just as he had so many other comments from John, and instead focused on their surroundings. They were standing in a small living area, which fed into a small kitchen. The countertop was littered with old leather-bound books, and numerous documents were strewn all around the floor.

"Spacious," John tried joking. "Although it's a pity they didn't bother to tidy up before having company."

Sherlock and John took many moments to took around the flat and decide what details would be relevant to finding the bomber that had fled from the location in an obvious hurry and which were merely anecdotal. Well, we must be fair; it was mainly Sherlock pointing out the meaningful elements to the scene and him ignoring John's observations. Don't get me wrong, there were indeed moments when John had noticed something of importance, but Sherlock was "in the zone" and didn't hear his words. Moments later he would repeat John's very same remarks. John would just roll his eyes at such ignorance and continue to wonder what drew him to such a character.

"Ideas about where this guy has run off to?" John inquired as Sherlock continued to pace the floors. It was then that Sherlock's foot fell upon an area of the floor that had not yet been visited. He felt his weight shift in a strange way upon the sole of his shoe and froze as a metallic click reached his ears.

"John?" he breathed, completely still.

"Hmm?" John responded, seemingly bored.

"I've just stepped on a bomb," he said flatly. This got John's attention.

"What?"

"A bomb, John. It's under my right foot," Sherlock clarified. "It's set to react as a mine would, responding to the weight placed upon it. It's going to detonate if I step off of it."

"Are you sure it isn't just a bad floorboard?" John asked hopefully. "I mean, this place is old."

Sherlock scoffed. "You think I can't tell the difference?"

John's frozen stance matched Sherlock's. "What do we do?" he asked, knowing that Sherlock would have an answer. After all, he always had an answer.

"Get Lestrade," Sherlock sighed.

"Well, it goes without saying that you shouldn't move for the time being," Lestrade told Sherlock.

"If it goes without saying, then why did you say it?" Sherlock crooned. Lestrade ignored him; it seemed that they were getting pretty good at ignoring one another.

"I have a team scanning the area for any other bombs, but so far, you seemed to have found the only one."

"Of course, he found it," John said, not sure if he was trying to turn that into a joke or not. One glare from Sherlock told him that he wasn't.

"Sir," an unfamiliar officer said from the doorway to the flat. "You were right; the only one is there," he finished while pointing at Sherlock's foot.

"Thanks," Lestrade said dismissively. The stranger nodded and left as quickly as he had entered.

"So, what now?" John asked. He was doing his best to decode the situation on his own, but this one was slightly out of the ordinary for him.

"I have investigators trying to find our perp, and meanwhile, our bomb team is going to snake a camera into the floor to get a better look at that device," he said with another nod toward where Sherlock was standing.

"Can't we just try the old Indiana Jones trick?" John asked, trying his best to sound serious. "You know, throw something of equal weight on top of it and yank Sherlock off at the same time?"

"Don't be absurd," Sherlock grunted. "If my observations are any indication, then this device is extremely sensitive. Even the slightest movement of my body or the tiniest shift in weight could set it off." John swallowed hard.

"Then is using that camera safe?" John asked Lestrade.

"As a precaution, we'll come in sideways. We've considered a radius of about 1 meter, so stay at least that far from him, got it?" John nodded stiffly. "Until then, sit tight." Then Lestrade was gone, just Sherlock and John left in the flat. John glanced around, trying to figure out how he was going to pass the time. 'Might as well make myself comfortable,' he thought and pulled a padded barstool away from the countertop.

"What are you doing?" Sherlock inquired, seemingly offended. John looked up inquisitively at him before he had the chance to sit down.

"I, uh… you're the one standing on the bomb," he said, thinking it should be obvious as to why he had the freedom to sit while Sherlock did not.

"You're trying to babysit me," Sherlock decided.

"Well, I'm not leaving," John shot back as he defiantly sat down, leaned against the counter, and stared at his friend.

"What good are you staying here? You should be corralling Lestrade and the rest of his clowns. God knows they need any help they can get."

"I'm not leaving," John repeated. "Lestrade will figure something out."