Reika's daughter and son-in-law were forced to move out of their apartment due to demolition, so they decided to temporarily live with Reika until finding a new home. For Reika, who had been living alone since her husband's passing, having her daughter's family stay with her brought great comfort. However, a small issue soon emerged within the couple's daily life. The son-in-law desired sex every night, but the daughter refused him, leaving him to resort to masturbation each evening. One night, Reika witnessed the scene again and scolded her son-in-law. In response, he pleaded, "If masturbation is wrong, then why don't you let me have sex with you, Mother-in-law?" Unable to resist, Reika gave in to his desire—just this once.