I was unpopular and wanted to lose my virginity, so I tried summoning a succubus or something like that. Then my sister opened the door to my room just as she appeared! In the magic circle... there is a succubus who possessed my sister's body! I lost consciousness and when I woke up... there was no magic circle or my sister... Is it a dream... However, the lewd demon gradually became able to control my sister's body freely and started an incestuous act.