I'm not popular with girls, so I wanted to lose my virginity, so I summoned a succubus as a last resort. But just as she appeared, my sister opened the door to my room! In the magic circle... was a succubus possessed in my sister's body! I fainted, and when I woke up... the magic circle and my sister were gone... Was it a dream? However, the incubus gradually gained control over my sister's body, and came to milk me of my semen with raw sex and creampies, not caring about our incestuous relationship! What if my sister gets pregnant with my child...? Sweat.