Waka lives with her mother and her stepfather's son Masato, who is remarried while Waka is away on business. Masato and Waka are not related by blood, but before they know it, they have a physical relationship. They keep it a secret so no one will find out, but their relationship is discovered by their uncle. Waka's uncle becomes attracted to her young body and forces her to have sex with him without telling him...