Daichi and Chiharu's only son, Yuta, is hospitalized at a university hospital in Tokyo with an incurable disease, and surgery would require a huge amount of money. - A wealthy man named Yanagi is willing to pay for Yuuta's surgery in full if conditions are met, so when Daichi and Chiharu go to see Yanagi directly, he presents one condition: ``I want to hire Chiharu as a sex slave for one year.'' - . - Daichi was strongly against it, but due to Chiharu's strong desire to help Yuta, he signed the contract.