Sou Kurosaki is determined to lose his virginity and stop losing love interests to his childhood friend, Kazushi Haita. Haita belittles Sou's attempts to find a superior girl, so Sou seeks out a supernatural woman to prove him wrong. After multiple attempts, he summons Kogure Deimon, a succubus, only to discover that the beautiful woman is actually a man. Shocked, Sou runs away and returns home to find that his supposed cousin, Kogure, is now living with him. Kogure cannot leave until his task is complete, so he decides to blend in with Sou's daily routine and deflower him by any means necessary.
