Haitoku no Shoujo - Season 1

Hiroko accepts a tutoring position at an elegant mansion, where she is to instruct a young girl named Yuki. After consuming tea prepared by Yuki's sister, Shizuka, Hiroko loses consciousness. She awakens to find herself restrained and unclothed on a bed. Hiroko becomes the subject of various sexual acts performed by Yuki and Shizuka, who employ toys in their activities. A disturbing family secret comes to light during this ordeal. The narrative follows Hiroko's attempts to resist and questions her ultimate fate as she is exploited by the two sisters.