Recently dissatisfied with her relationship with her husband, Yuki finds herself spending more time masturbating alone. One night, she accidentally catches her son-in-law Atsushi, who lives with her, pleasuring himself. Instantly captivated by his massive, powerful cock, Yuki becomes obsessed. His entire body exudes irresistible charm, and drawn to him, she proposes to help relieve his sexual needs, saying, "Let me do it instead of your unwilling daughter." From morning till night, she seizes every opportunity to devour Atsushi's huge cock, repeatedly milking him dry. Overwhelmed by these intense encounters, Atsushi gradually loses the ability to think with anything but his lower half, surrendering completely to her relentless seduction. As a result, his feelings and actions begin to shift, giving rise to an entirely new relationship.