When a little girl named Mio wants to save her brother from violent beatings, she turns to Ren and Rai to put an end to the brutality. However, it all might just be a prelude to greater violence. Seventeen-year-olds all around the world have been receiving the same message: "My name is Angel. I'll save you." But will this mysterious message really lead to a savior, or to the doom of them all?