Mizuki, a married woman, began living with her husband's family after marrying her childhood friend. On the surface, they appeared to be a happy couple, but Mizuki carried a secret concern—her brother-in-law Kazuo had become a reclusive shut-in. Worried about Kazuo, who was once her close friend, she visited his room. What happened there took an unexpected turn when Kazuo forcefully kissed her. His passion was unlike her husband's—intense, relentless, and deeply arousing. Gradually, Mizuki's emotions surged, awakening feelings she had never known before.