Tsubaki Kato is a slender milf married to Takayuki, whose demanding sales job and self-centered, neurotic personality keep her constantly on edge at home. Her only solace is the quiet time she spends alone, slowly bathing while her husband is away. One day, Takayuki brings home his subordinate, Kanda, who had soiled his suit during a work visit, and allows him to use their bathroom. At that very moment, Tsubaki is soaking in the tub, indulging in masturbation to ease the loneliness of being neglected by her husband. Unexpectedly, Kanda walks in and catches her in the act, setting off an intense and irreversible encounter.