Yuichi marries into his wife's family, but every night his thoughts drift to Kaori, his voluptuous mother-in-law with overwhelming sex appeal. Even while having sex with his wife, he cannot stop picturing her enormous breasts. Unable to contain himself, he confesses his desire. Thrilled to be wanted as a woman, Kaori unwittingly seduces him until her long-dormant lust erupts and he lunges for her huge tits.