Sterek AU: Falling in love with a cold blooded assassin like Stiles Stilinski was never the plan. Just sex, Stiles had said the first time they fell into bed, just this. But life rarely goes according to plan and Derek found himself too close to the point of no return, too close to getting his heart irreparably broken. When he decides this needs to be the end for them, the end of a life of always second guessing Stiles and inevitably getting hurt, he’s expecting Stiles to just walk away, to keep going with his life as though Derek was never in it. Love, after all, had never been part of the deal.
As it turns out, they’re both good at breaking the rules, at least when it comes to each other.