Shun, the mother, is exhausted from handling all household duties alone while her husband is away. Her son, Hiroki, notices her fatigue and wants to help. When he asks a friend for advice, he's told, "Just give her a massage to relieve her tiredness." Hiroki immediately decides to massage his mother. Her firm upper arms, large breasts, and toned thighs glisten erotically under the oil, arousing him further. His hands move toward her groin, gently kneading her plump mound with his fingertips. With pent-up desires from her unsatisfying marriage, the mother offers no resistance, honestly accepting Hiroki's sudden kiss.