Hentai is based on a manga by yoshiron. Incest in the family is common in hentai and this one is no exception. The main character Nanakura Kasumi-chan has been abused by her father for a long time. It all started when her mother left her for another man and her father mercilessly went on a binge. Now Kasumi is determined to go to Tokyo University and get away from her unbearable life.