To secure his brother's debt, younger brother Tsutomu begins treating his sister-in-law Satsuki as an object to satisfy his sexual desires. Their acts soon involve Satsuki's nephew Kenji as well, and the two start using Satsuki together as their shared sexual toy. Though Satsuki realizes she still loves her husband, she is subjected to intense training like vibrator penetration and double deep throat, gradually beginning to feel pleasure from it. The belief that only her husband owns her slowly crumbles away. Satsuki is no longer merely her husband's possession.