Trying to be cool about it - TWXTMR

"Stiles," He started hesitantly. "These men are from the FBI." Yeah he had actually figured that one out thanks. "They are here because, because um- Fuck this difficult." He sat down on the ottoman next to him, head in his hands, as the two agents sat in chairs on the other end of the coffee table. "Okay" The sheriff inhaled sharply "They are here because of Stephen. He's alive." Stiles froze. He could tell his dad was still talking but he couldn't hear him, all he could hear was the sound of static, like his mind had panicked and shut his ears off before his brain blew up from the shock.

Or

Stiles had a twin brother, Stephen, who went missing when they were only three. Fourteen years later he's back, with a new name and a new family, rescued from some crazy fucking experiment Stiles can't even begin to wrap his head around, but he's trying. Problem is, it feels like Thomas isn't.