Mahiro, who has returned to his hometown to announce his marriage, goes to his older sister Hibiki, who has been a good friend of his since they were young, to report the news. He is happy and excited to hear the news... but in Kokoro, Hibiki is mad with jealousy because Mahiro has been taken away from her. Unable to suppress her intense feelings, Hibiki puts Mahiro to sleep, restrains him, and devours his body with all her lust. Bondage training, forced face sitting, toy torture, oil torture, forced continuous orgasms... Unable to resist, Mahiro is subjected to seemingly endless training, and before long, both Kokoro and body are subjugated to the ropes...