A/N: Just quickly, I don't know a lot about tattoos so hopefully all my explanations make some sense when we get to that point. =D
John stormed up the stairs into the flat and slammed the door harder than necessary. Sherlock was jolted out of his thinking by the bang. He glanced over at his flatmate. If there was one thing that Sherlock could not miss about John, it was that he was neat about his appearance. But tonight, John looked rumpled. His shirt was only half tucked in, and his jumped was all askew. He also had a box of stuff under his arm. It was all stuff that Sherlock hadn't seen in a while but recognized as John's belongings. A couple of pictures, a jumper and two t-shirts as well as one of John's favorite books that he had lent to Sarah were all in the box. These were all things that Sherlock recalled he knew John had taken to Sarah and from that he realized there was a break up with Sarah. John had been going over there more and more frequently much to Sherlock's annoyance. Sherlock wanted John to be home making tea and solving crimes rather than spending time with Sarah. Somehow they had decided to give it another go. Sherlock disappeared for three years and as soon as he came back John started seeing her again which irritated him more.
Considering the care that John had used to dress and prepare for this evening, even buying extra milk so Sherlock would have some the next day, Sherlock had not expected him home tonight at all. So what was the problem now?
"Back so soon?" he called over to John who had begun to make tea. A grunt was the only reply he received. John continued to slam things around in the kitchen.
"I assume you brought all of your belongings home because she…," Sherlock didn't finish the sentence. John had turned around and was glaring at him.
"So ummm, er, what happened?" Sherlock asked trying to ask rather than assume. Even though he found it brilliant any other time, it often annoyed John when Sherlock deduced things about his personal life.
"If you're so bloody brilliant, why don't you tell me?" John grumbled. His face showed how much he instantly regretted the words. Now free to deduce, Sherlock jumped out of his chair at this challenge and walked over to John looking him over.
"Alright. You spent quite a bit of time preparing for this evening. You expected it to go rather well, maybe even expected to stay at Sarah's but not on the couch judging by the amount of cologne you were wearing when you left. But something went wrong. Very wrong and you brought home all of your belongings. She boxed them up so you are not invited back. Now, you're upset, but you're angry not sulking so I assume you broke up with her. There was an argument and judging by the state of your clothes after you made it into the bedroom so it was something physical, probably about you. Since you got upset and you broke it off the problem was with you …but what was wrong?" Sherlock said all of this very quickly just a few inches from his flatmate's face while John's hard stare grew more and more icy.
"Right, I'm going upstairs," John growled through gritted teeth. He walked away from Sherlock and left the tea on the counter.
"Oh, and I would say this had something to do with size, but since the only piece of clothing that looks disturbed is your shirt…I would say this has to do with your upper half. My guess is your scar." Sherlock surmised. John paused.
"Close Sherlock, but no not the scar,"
"Damn, there's always something," Sherlock grumbled as John pounded up the stairs to his room. He tried to go back to thinking about the serial killer that was making their way around London, but John's problem kept pulling at him. He tried to shove the insignificant mystery into the back of his mind. What would make Sarah push John away? What would disgust her? Frighten her? Anger her? He kept going around in circles trying to piece together what could be under John's clothing that would cause a reaction like that. He couldn't quite figure it out so he went back to the serial killer.
John came downstairs in the morning without a jumper. He was wearing just a long sleeved button up shirt. The sunny weather in London often did not get hot enough to make him go without one, but this morning it was quite warm out. He wasn't exactly happy about just wearing a button up shirt. The very thought of wearing just a t-shirt made him twitch. Last night with Sarah had been awful. Then he came home and Sherlock saw everything, saw right through him. Sherlock didn't know his secret but now he was interested and that meant he would know soon. Just the Sherlock skipped downstairs in his blue bathrobe and pajamas and lit the fire.
"Why the hell?! did you light a fire when it is the warmest day of the year?" John screeched.
"Experiments," Sherlock shrugged. In truth he was experimenting, but on John. John was upset from his break up with Sarah. He probably wouldn't be going out today unless forced. It was also warm. If he made it warm enough, he might force John into changing into different clothes and then Sherlock deduced he might be able to find out what John was hiding under all his clothing.
After about an hour, John unbuttoned the top buttons on his shirt. He was reading on the couch against the far wall and right under the smiley face. Sherlock saw the quick movement and grinned as he continued to research on John's laptop. He had looked through all the folders and the bookmarks. There was nothing about surgery or scaring. Sherlock continued to think in circles.
Another hour. One more button.
Sherlock got up and started examining a slide on his microscope.
"Come here and look at this."
"Just come over here."
John got up and moved into the kitchen. He sat down in front of the microscope. As he leaned in, so did Sherlock. John's shirt lifted away from his neck and his right shoulder just enough. Sherlock saw a patch of red and brown but he couldn't make out what it was.
"Tattoos," he breathed and instantly regretted it as it slipped out of his mouth. I think better when I talk aloud, he had once told John and old habits die hard. John stiffened. He stood up and looked at Sherlock for a moment.
"Experiments? You mean prying?" John steamed. He kept shifting his weight and didn't look away from his flatmate, but Sherlock wasn't listening. Instead he was using the new data to try and assess what went wrong on the date the night before.
"Sarah…tattoos? What is wrong with tattoos? My God, John if this is it then you are better off without her," It didn't make any sense to him. A lot of people had tattoos. Many people were proud of them, not just many people…almost anyone who did showed them off in some way.
"Leave it alone." John called. He pulled his jacket on and left the flat. Sherlock didn't see him for the rest of the day.
Two days later
The detective and the doctor were coming up the steps into their flat after another successful case. Sherlock was still pondering the patch of color he had seen under John's collar.
"Where?" Sherlock asked. He blocked John's path up the stairs with his body.
"Where," John repeated confused.
"Yes. Is it just the one on your shoulder or are there more?"
"No." John shoved his flatmate's arm out of the way and tried to go up the stairs.
"Why?" He had always been unaffected by John's need for privacy, but he couldn't resist any longer. He wanted to know what they were, where they were and why John was so determined to hide them.
"Why was she upset?" Sherlock continued to block his path.
"We're back to Sarah?" John rolled his eyes and continued to try and push Sherlock's arms out of his way.
"I don't want to talk about it with you Sherlock."
"Who else will you talk to it about then?" It was a low blow and Sherlock knew it but he wanted answers. "You're afraid I'm going to reject you if I see them because the last person you trusted did, right?" Sherlock had walked around to the front of John.
"Everyone rejects me."
"When have I?"
"You're not the most reassuring person in the world, Sherlock!" John roared.
"But I have never rejected you. I accepted you into my life the moment you stepped into the lab at Barts." Sherlock met John's gaze but he looked away.
John was silent. Sherlock waited. He didn't deduce anything. He just waited. Waited for John to decide. He wanted to know so badly it was almost torture to keep his fingers from tearing the clothing off of John.
"No." Sherlock dropped his arm and followed John up the rest of the stairs.
"Damn," Sherlock swore and moved into the kitchen to start working on experiments again.