Yuko, a mother, is staying with her daughter and her husband while her husband is away on business. - She was living a lonely life without being able to meet her husband, but she was not alone in her loneliness. - Her son-in-law, Tooru, is also always masturbating alone at night, and when Yuko finds out, she doesn't feel like it's anyone else's problem... - Yuko, who knows how painful it is to not be satisfied with her sexual desire, tells him that her daughter's responsibility is hers and invites him out every chance she gets. - But before she knew it, in order to satisfy her own sexual desire, she started seducing her son-in-law all the time because he wanted his big dick...