Is Seijo coming back?

During the summer when he was 17, his private tutor Ozawa Maria, who was then a university student, left him with this last message, "I'll be your girlfriend after you qualify for university and become an adult." Then she suddenly disappeared from his life. He still dreams of her sometimes. Even now. 10 years later, they are reunited; she as a serial murder suspect and he as a lawyer. Although his feelings waver between love and contempt, when their bonds are established again, a heartrending, maddening love story begins. Is Maria a wicked woman or a saint?