One day, Itsuki loses her house keys and can't hold her bladder while waiting at the front door. In desperation, she asks her neighbor, Imaoka, to use his bathroom, but she can't make it in time and ends up peeing right there in the entryway. Apologizing profusely, she's shocked when Imaoka—long captivated by her voluptuous body—uses her accident as leverage to manipulate and dominate her. He becomes particularly fixated on her anus, probing and stimulating it intensely, awakening sensations she's never felt before. The deep, unfamiliar pleasure rewires her mind, making her crave more. When she visits Imaoka's place again, a whole new experience awaits—one that pulls her deeper into anal play, control, and submission.