Rika, a mother who has raised her son Mamoru single-handedly. Recently, she seems to be in a relationship with a colleague of her company, and Mamoru, who is a mother's boy, doesn't like it. That feeling is so strong that Mamoru sneaks into his bed and crawls at night. One day, Rika brought her lover to her house. Mamoru leaves the room, revealing her displeasure, but when he returns to the room, he finds Rika intertwined with her lover! Shocked by her obscene appearance, Mamoru returns to Rika's bedroom to make her mother his own.
