Kokoro comes to the Sagawa family as a stepchild of her mother who remarried. However, her mother soon leaves. To Kokoro on her mother for leaving, her stepfather and son sexually abuse Koharu. They slap her mercilessly, forcefully deep-throat her, and make her urinate in humiliation. Abandoned by her mother and raped by her stepfamily, Koharu becomes depressed. However, no matter how terrible things are done to Kokoro , Kokoro endures, telling herself, "I'm not like my mother. I won't run away." Where on earth will this crazy family head?