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Kaoru wants Kyoshiro's girlfriend, Tsumugi, for himself. He meets Kyoshiro in a chat room and they make a contract. Kyoshiro and Kaoru will take turns training Tsumugi to be a sex slave, and they'll record their progress on a website. At the deadline, all the site's visitors will vote on which one of them deserves to be Tsumugi's boyfriend.
(Source: Anime News Network)