Rinka, a wife who lives with her husband and father-in-law. My father-in-law's dementia progressed, and he was in an uncontrollable situation, sprinkling urine in the room. However, one day during nursing care, Rinka witnesses her father-in-law, Ichimotsu, standing upright. Unlike ED's husband, Rinka involuntarily tries to get rid of her father-in-law, Mara, who erects even when she is old ... But after that, her father-in-law demands sexual treatment from Rinka every time! Mouth is the beginning, caressing even stinky and unsanitary anal, and finally the end is mercilessly screwing in Mara and ejaculating. Rinka, who was unwilling at first, gradually became happy with her affair with her father-in-law.