Juri married her coworker and became a full-time housewife. Her husband is currently on a long business trip and she lives with her daughter and son-in-law. However, she feels lonely without her husband. One day, she accidentally finds out that her son-in-law, Ichiro, has an incredibly large penis. Captivated by his large penis, Juri continues to make obscene advances day and night, saying, "I'll take my daughter's place..." Unable to resist his mother-in-law's lewd behavior, Ichiro crosses the line and becomes addicted to the pleasure.