Marina and Rena, close mommy friends, are having their usual tea party when the conversation turns to sex. Rena seems to be having a fulfilling sex life with a young man she met through an app, and despite her introverted nature, she half-heartedly suggests the app to the hesitant Marina, saying, "Just once..." Through the app, they meet Shintaro, a compliant and innocent young student. As Marina experiences the thrill of dominating a younger man, she gradually becomes consumed by the dangerous game with him, both mentally and physically.
