Mihong works at an ear cleaning spa to raise her son alone after losing her husband. One day, a regular customer named Takekawa proposes to Mihong, who is worried about her son Kazuya, who has been shut in his room for a long time. She visits the Shut-in Center for advice and enters Kazuya's room. There, she finds him watching incest AV involving mothers and sons. Understanding Kazuya's feelings, Mihong makes a mistake with her son just once, but this leads to an irreversible tragedy...
