Sae, the beautiful daughter-in-law, lives with her worthless father-in-law, Shigeharu, who is crude, irresponsible, and addicted to gambling. Shigeharu has long been obsessed with Sae, routinely spying on her in the bath and stealing her underwear to sniff. One day, Sae's husband, Makoto, announces a two-night business trip. Seizing the opportunity, Shigeharu drops his facade and violently attacks Sae. As she desperately tries to escape, he overpowers her and pins her down, his engorged cock ready to invade her.