Based on the game by ruf.

Kaoru wants Kyoshiro's girlfriend, Tsumugi, for himself. He meets Kyoshiro inside a chat room plus they make a contract. Kyoshiro and Kaoru will take turns training Tsumugi to be a sex slave, and they will record their progress on-line. In the deadline, every one of the site's visitors will vote which one of them has to be Tsumugi's boyfriend.