Mother Maki is drawn to her son Takuya's part-time coworker, Tetsuo. One day, when Tetsuo comes over, they relax together drinking beer, and Takuya, being weak with alcohol, quickly falls asleep. That night, the slightly intoxicated Maki and Tetsuo unexpectedly end up having sex right beside her sleeping son. However, Takuya suddenly wakes to the sound of his mother moaning passionately and becomes overwhelmed with intense jealousy and confusion toward Tetsuo. These shifting emotions deepen the story, creating new tensions that ripple through their relationships.