After losing her husband, Mikuru works at an ear-cleaning salon to raise her son on her own. One day, Mikuru is proposed to by Takekawa, a regular customer, and worries about Kazuya, who has become a recluse, so she consults the Recluse Center. After receiving advice from the center, Mikuru goes to Kazuya's room and finds an adult video of mother-son incest. After learning about Kazuya's feelings, Mikuru makes a one-time mistake with her son, but it leads to a tragedy from which there is no turning back...