Living in the apartment managed by their parents are the brother's wife and her husband, along with the younger brother. The serious and hardworking older brother contrasts with his taciturn, middle-aged NEET younger brother, who harbors abnormal and sexual feelings towards his sister-in-law (and aunt by marriage), Saki. One day, Saki gets caught in a sudden downpour and becomes soaked through, triggering something in her brother-in-law. Seeing this, the younger brother subjects his sister-in-law to grotesque humiliation. Saki's wet, cold clothes steal away her body heat and reason, plunging her into an abnormal situation where she feels her own body growing hotter.
