Lee Han is facing a miserable life until he receives a sinister offer: become an apartment manager and fulfill a twisted task: sexually engage with the female residents. The terms are chilling: "Sleep with the women living in this building—whether through blackmail, seduction, or even force."

Lee Han accepts this morally compromising yet lucrative deal, viewing it as his only chance to escape poverty. His new job turns into a high-stakes game of manipulation and pursuit. He must quickly identify the vulnerabilities of the women around him to achieve his goals.

His first target is the beautiful, married woman in Apartment 301, Su-Jin Han. Lee Han finds himself deep in a psychological battle, desperate to uncover her weakness and exploit it. This new role tests the limits of his morality, thrusting him into a dangerous spiral of desire and dark secrets hidden within the walls of the apartment complex.