(I'm back :3)

"They didn't make a mistake," Sherlock replied with quite a lot of certainty. "First of all, they never do, and you're obviously a wizard. So don't worry about it, okay." He tilted his head slightly, just watching John in a curious manner. He did find the other boy... Interesting. It was all weird to him. He wanted to be nice to John, he wanted to be his friend. Sherlock didn't have friends. He had acquaintances and people that were useful to him and not friends. "And I'm not insulted. Others will be..." He trailed off. "Some wizards don't like people like you, John. Because you're... The term is mudblood. You know, not of a wizard family. I thought it would be nice to warn you." He shrugged. "And it's quite easy. There's rules about performing magic in front of muggles. Also, underage magic. We're not allowed to use magic out with of school so that generally saves any spells that are a mistake. Also there are spells to remove the memory." He noticed that John was obviously nervous and also uncomfortable... He wasn't sure what he should do to make him feel any better.

There was a knock on the door before it was opened and a boy stuck his head in. He was obviously older and seemed to already be in uniform, wearing a prefects badge. "Hey, Sherlock, thought I'd just check in on you while it was my turn to patrol the corridors," Greg smiled at the two in the carriage, to which Sherlock scowled in reply. He had been quite enjoying just talking to join and now that had been ruined. Greg turned to look at John with a friendly grin. "Well hello! I'm Gregory Lestrade, though I prefer to go by just Greg. Who might you be?" Considering that he was still in the carriage with Sherlock he had not been scared off yet. That was definitely a good thing. Greg would have to tell Mycroft when he got back to the Prefects carriage when his turn to patrol was done.