Ryosuke Kamiya is an ordinary university student whose world is turned upside down during a private moment. While watching an adult video, he is shocked to recognize the main actress as Ruka Someya, his quiet and reserved classmate from the same university seminar. Confused and unable to keep the discovery to himself, Ryosuke confronts Ruka in private. Instead of denying it, she confirms his suspicion and calmly asks him to keep her secret. To ensure his silence, she proposes a deal that will completely change the nature of their relationship, binding them together in an awkward and tense alliance. The story is set in a contemporary Japanese university, focusing on the daily life of a small seminar group, which creates an intimate pressure cooker where the protagonists cannot avoid each other. The central conflict arises from the double life led by Ruka Someya, who maintains a perfect facade as an ordinary coed while secretly working as a professional adult actress. Ryosuke, now burdened with this knowledge, struggles to reconcile the two versions of the girl he sits next to in class. A notable narrative arc follows the development of their secret contract, forcing them into a series of private encounters that blur the lines between blackmail, genuine connection, and mutual exploitation. As Ryosuke gets drawn deeper into Ruka’s hidden world, he begins to uncover the circumstances and motivations that led her to this career, moving the plot from a simple secret into a more complex exploration of personal boundaries and unexpected intimacy.