A tragedy from eight years ago. When Yuki turned 18, her virginity was taken by her mother's new husband, Kentaro. Since that day, her relationship with her "stepfather" has continued... Yuki has no one to talk to and has become nothing more than a sex toy. But then spring comes to Yuki's life. She marries the man she loves. Yuki was supposed to find a little happiness in her hands... But a few months later, her husband's father, Ryozo, finds out about Yuki's relationship with Kentaro. From that day on, the brutal training of the two "stepfathers" who are not related by blood begins...