Chiaki is a single mother who has raised her son Kenji. However, as Kenji grows up, Chiaki decides to remarry a man who has been interested in her for a long time in order to find happiness as a woman. A few days later, she goes on a family trip with her new husband and Kenji. However, Chiaki is the only one who looks gloomy. When she lifts up her skirt, she is revealed to be without underwear... and a remote vibrator pulsating between her legs... It was all planned. By her beloved son Kenji...