Recently, Mako has been experiencing an unusual condition where even slight stimulation makes her nipples extremely sensitive. As a young married woman, she feels confused and troubled by these changes in her body. Unable to muster the courage to talk to her husband, she suffers in silence—until one day, her stepson catches her masturbating. Burdened with anxiety and shame, Mako decides to open up to him. As he listens with empathy, he begins to confront his own growing feelings for her...