So I am going to RP as Sydney Harrison, my OC. This time she and Sherlock knew each other during his drug days. She introduced him to heroin and she supplied him with it. I'll work out a little more of a back story with who ever Role Plays Sherlock. So it's been years and Sherlock hasn't thought about her in ages. So when he starts getting anonymous clues to a drug dealing case he doesn't have any idea who it could be. She is in the middle of a problem that Mycroft has told Sherlock to look into, but he's making sure John keeps a close eye on Sherlock and makes sure he doesn't get high. When Sydney finds out Sherlock has gotten involved she starts to help him by texting him little clues. She's clean, but got stuck in the system and hops Sherlock can get her out alive.