Masami was visiting her daughter and son-in-law's house to mediate a fight. She wants her daughter to be happy. And if possible, she wants to meet her first grandchild. It was an action born from pure feelings, but the reason for their discord was that her son-in-law was secretly lusting after Masami. That night, Masami, who ended up staying at her daughter and son-in-law's house, relaxed, took a bath, and went to bed in light clothing. Masami didn't realize that such casual actions were stimulating the forbidden desires that her son-in-law harbored.