In order to save the life of his son who is suffering from a serious illness, Katsuhiko's wife Mio makes a contract to become a sex slave for a wealthy man named Tezuka for one year. Even though it is for his son's sake, Katsuhiko laments his own helplessness in having sold his beloved wife. The videos Tezuka sends every week record the entire process of Mio being trained, and Mio Mio initially shows a strong attitude, she gradually becomes Tezuka's Kokoro...