There was a secret in her mother, Grace, who lives with her husband, son, Seiya. I love my only son, Seiya, but I was hiding behind my husband and doing sexual treatment in order to get rid of my anxieties. However, the obscene behavior that my mother thought was good had inflated my son's hidden desires. Seiya began to want to have sexual intercourse with her mother, and she couldn't control her desire. Grace couldn't resist Seiya's request when she looked back on her actions, and finally crossed the forbidden line ...