Lunary and Luni,twins brother sister on age 17 and still studying. Lunary is a shy,anxious and clingy person while Luni are joyful,energetic and smt serious person. Yes,they're different,yet they still love each other. But only one thing that Lunary doesn't like about Luni,that is he is a killer. Only she know about this,and she need to keep this as a secret between them both,only them..