Rina's husband has recently become cold toward her, and unsure of the reason, she confides in her father-in-law. However, instead of offering serious advice, he pulls her into his arms and repeatedly engages in lewd acts with her. Under the pretense of teaching her how to seduce her husband, he continues to have sex with her again and again. Gradually, Rina loses herself in these feelings, drifting further away from her relationship with her husband.