Satoru Kido, a private detective is hired by Shibata, the butler of the Nakako family to investigate a stolen family heirloom, a ring with a red ruby on it. So Satoru and his personnal assistant May questionned those that lived in the Nakako\'s household. There\'s Ayano, the daughter of the landlord - Kaoru Tanimura, Ayano\'s tutor - Nosomi Watase, the maid and the butler. However, Satoru doesn\'t know what dark past this family has and this house seems familiar to him. Satoru will enter a world where passion, betrayal and deception rules in this household. Will he ever found the stolen ring ??? Will he discover the dark secrets of the Nakako\'s family ??? Will he find the suspect to the case ???