Reiko visits her son and his wife to celebrate the birth of their first grandchild. The son and his wife welcome Reiko warmly and have a lively conversation after a long time. That night, the son accidentally sees his mother taking a bath. The son becomes excited by his mother's naked body. Late at night, he longs to have sex with his wife, who he hasn't seen in a while. However, his wife rejects him again. The son's heightened sexual desire seeks an outlet. He sneaks into his mother's bedroom, gently lifts the futon, and begins to play with his mother's crotch. Her genitals gradually become moist. The son ejaculates with all his might onto his mother's pubic hair. The mother watches her leave with half-closed eyes, wiping away the semen that was about to be ejaculated, and is troubled by her son's strange behavior. The next day, the wife goes out, and the son, left alone with his mother, suddenly embraces his mother and begins to caress her roughly. The mother refuses, but she cannot overcome her son's strength and tries to calm him down with her mouth and hands. The final line was crossed, but the son's intense desire reminded the mother of her forgotten womanhood. Late at night, unable to sleep, the mother begins to console herself in secret. Her heartbeat gradually gets faster. Her fingering becomes more intense with the desire to satisfy her womanhood. Her ripe body comes countless times but is never satisfied. As if he could see right through her, her son appears before her. The mother, whose body is already receptive, is unable to completely reject her son and ends up being penetrated by her son's hard rod. The joy of having her vagina filled envelopes the mother in pleasure and she instantly reaches climax...