Tsukishiro Michiru keeps dreaming about a castle. In it, five jewels have taken the shape of men—each one possessing a personality that falls somewhere between cruel and dangerous. The master of the castle gives her an instruction: choose the jewel that suits her best before the next full moon. In her waking life, she encounters five men who look exactly like the jewels. They are warm, charming, easy to be around—everything the dream versions are not. She cannot determine if they are the same people. She has until the next full moon to decide.