Kido is a private detective. One day, he receives a job offer. It is simply to guard his client. He once tries to refuse it, but Mei, Kido's partner, tells him to accept it. Kido reluctantly accepts the offer and visits the client's house. There live Ayano, the client's daughter, Shibata, a butler, Imada, a janitor, Nozomi, a live-in maid, and Kaoru, Ayano's home tutor. Kido asks Shibata what his job is, but he just gives a vague answer. He doesn't know what to do, but he gradually gets to know the secret of the family....