Aozawa Kanata is a first-year university student. Upon entering university, she ends up sharing a room with Ichinose Yui, the daughter of her father’s friend and a third-year student at the same university. However, once they start living together, she learns a shocking truth: Yui is a lesbian, and is known for being a notorious womanizer. This is a university roommate story about a straight junior who is seduced by a beautiful, lesbian senior.