While their parents were away, the eldest and second sons were left alone to care for their sick grandfather. Suddenly, their third brother Hikari, who had transitioned into a newhalf, returned home. The brothers were shaken by her stunning beauty and began to desire her intensely. Hikari, aroused by the relationship with her brothers, confessed, "I want to do it with all three of you...!" and sought to build a new bond with them.