Kaori is a housewife living with her husband and son. After reading a magazine article stating that sexual activity activates female hormones, she decides to reconnect with herself by embracing her husband again after a long time. Her son secretly watches them, and the next morning he experiences a wet dream. As he tries to sneak out while hiding his soiled underwear, Kaori finds the semen-stained pants while cleaning. That night, Kaori tells her son that "not having sex regularly can negatively affect your health." At first, she agrees only to help him with her hands, but at his pleading, their relationship gradually deepens...