Ichika Matsumoto's mother has been remarried for 10 years, and her stepfather is very kind and takes good care of her two children. However, her mother suddenly fell ill and passed away, leaving her alone with her stepfather in this world. Just when the sorrow of losing her mother had not yet faded, Ichika was shocked to find out that her stepfather was a beast; unable to cope with the loss, he used his wife's own daughter as a substitute...