In the film, there are four stepmothers played by beautiful actresses. Although the film is divided into four separate parts, the content is the same. After getting married, the husband's sons were all grown up, so incest seemed to be an unsurprising occurrence in Japan. When the husband works far away and the wife lacks affection, the sons all understand what that feeling is like, so they want to replace their father and compensate for their stepmother's love. The mother sees her son wanting her as much as possible. So, my children were still young and wanted to teach them more about love, so they easily accepted.