His games are deadly to play, they're hard to win

A string of disappearances are occuring throughout Hogwarts. No one knows what's causing them. Harry, begins to notice a Ravenclaw losing her mind. Then Hermione and Ron are forgetting what to do to find out what's causing disappearances. Harry takes the situation into his own hands, facing something much worse than Voldemort. It's all AU. Rated T, because of slight violence.