Rena, a daughter-in-law, is relieved that her sudden move to live with her father-in-law, Ginji, is going smoothly. Meanwhile, Ginji, sensing that she is not satisfied with her indifferent husband, Akio, gives her a massage under the pretext of treating her sore muscles from her recent early morning jog... Rena readily accepts the request, but Ginji takes the opportunity to attack her sensitive areas. Rena begins to feel her body heat up and tries to resist, but it is too late. Ginji, with his rationality now out of the way, turns into a beast...