Visiting my mother at night

Rika, a mother who has raised her son Mamoru by herself. Recently, she seems to be in a romantic relationship with a colleague at work, and Mamoru's mother, Mamoru, doesn't like it. This feeling is so strong that before he knows it, Mamoru sneaks into his bed and crawls out at night... One day, Rika decides to bring her lover home. Mamoru leaves the room expressing his discomfort, but when he returns to the room, he finds Rika entangled with her lover! Shocked by her lewd appearance, Mamoru returns to Rika's bedroom to make her his own...