With her husband now unable to get hard, Sumire tries to exercise away her constant frustration. Then she discovers her son-in-law Shinya secretly watching her and masturbating. Unable to forget the enormous cock she accidentally sees, she claims she merely wants to help him relieve himself and begins secretly servicing him day and night. Driven nearly insane by the orgasms his mother-in-law gives him anywhere and at any time, Shinya finally...