Yuri, whose husband is often away on business trips, finds herself sexually unfulfilled and spends her nights indulging in nightly masturbation. One evening, Takeshi accidentally witnesses Yuri pleasuring herself and becomes instantly aroused. Unable to restrain himself, he approaches and seduces his own mother. Later, Takeshi goes even further by inviting his best friend over, exposing Yuri's body, and satisfying their mutual desires with her.