Newlywed Shizuka and her sister-in- Nanako have an intimate relationship that they cannot tell their husbands about. Then, suddenly, Shizuka's husband disappears. He promised to repay his debt by selling Shizuka's body to a debt collector. Nanako volunteers to become a slave to save Shizuka, who is falling into hell. The two are tossed about in a whirlpool of dizzying pleasure, and are transformed into beast-like figures...