When her father-in-law Genichi falls ill and requires care, Rena moves in with him. Once a notorious womanizer, Genichi begins to see Rena as a woman during the course of her nursing care, eventually developing deep romantic feelings for her. Overcome with desire, he starts aggressively pursuing her. Though Rena had been unsatisfied in her marital sex life, she gradually finds herself captivated by Genichi's experienced and skillful lovemaking. Their bond grows stronger each day, and they continue their intense affair during the daytime hours when her husband is away.