Yuuji is a clumsy part-time worker who is frequently scolded by his younger coworker, Takamiya-san. His home life is far more chaotic, as he shares his room with a mysterious, shape-shifting organism that is obsessively in love with him. By mimicking the appearances and personalities of the women in Yuuji's life, the entity seeks to seduce him and fulfill its romantic desires.
Yuuji struggles with his passive nature until Takamiya-san pushes him to be more assertive. To tempt him, she creates a biological duplicate of a high school swimmer, leading to a hedonistic encounter. However, the situation takes a surreal turn as Takamiya-san demonstrates her ability to assimilate others, blurring the lines between their identities.