Miki married a man with children. She dreamed of a happy married life, but her life changed when her husband's children came to live with them. She got along well with her younger brother Takashi, but her older brother Hiroki always got in her way. Hiroki was annoyed by Miki's kind attitude and when they were alone together, he pushed her down by force... Still, she believed in the bond between her family and thought, "He'll understand Itsuka," and from that day on, she began to spend her days as Hiroki's obedient sex slave.