While her husband is posted away from home, Yuka lives with her children and her son-in-law, Takeshi. Frustrated by the long separation from her husband, she discovers that her daughter and Takeshi have not had sex in a long time either. One night, Yuka catches Takeshi masturbating alone and cannot take her eyes off his enormous cock. Telling herself that she needs to satisfy her son-in-law in her daughter's place, she seduces him. From that day on, Yuka is obsessed with Takeshi's cock and wants her son-in-law around the clock.