Description: The main characters are the mother "Yuri'' and the twin sisters "Sakura'' and "Kaede''. Although the three of them are not related by blood, they spend their days together as a real family. One day, the two sisters forget themselves and attack the protagonist. Yuri, who witnessed the scene, happily announces that she is a succubus, and that Sakura and Kaede are also half-succubus. The protagonist accepts Yuri's proposal and begins a sexual life with his sisters who have become succubi.