The main character is invited to a house by her classmate, Reiko Tachibana, whom she has feelings for. He feels great to be invited to the house of his favorite person, but in fact, it is a trap by Reiko. He is fed a meal containing sleeping pills, loses consciousness, and is locked up in one of the rooms of the mansion.
Reiko Tachibana’s goal is to make the protagonist the new pet of the Tachibana family, and she tries to treat him as a toy to be played with sexually by the family.
Unable to bear such treatment, the protagonist aims to escape from the mansion. Can you escape from the mansion by fighting off the women of the Tachibana family and the maids who serve the Tachibana family?