Emi Tooda, the mother, visits her daughter and son-in-law, happy to see the loving couple. But one night, she accidentally discovers her son-in-law masturbating. Hearing his distress, she learns the truth—he hasn't been able to have sex with his wife, Emi's daughter, for months. Feeling sympathy, Emi decides to help, using her mouth and hands to relieve him. The next day, the son-in-law sneaks advances toward Emi when his wife isn't looking. Overcome by his passion, she finally gives in and sleeps with him. The long-awaited intimacy awakens Emi's long-dormant feminine desires, and she soon finds herself actively craving her son-in-law's body.