Looking for a story. Im really not sure what it would be rated. Im thinking M though. Heres what I remember from the story.

A girl is kidnapped by her half brother and his friends. They are some kind of secret society. Anyways I think she catches married men cheating on their wives as her job. The main leader of the "society" is kinda mean to her at first, even bruising her when grabbing her too hard. But not on purose. Anyways eventually after the girls helps with one of the "missions".

Does anyone know what im talking about?