When the down-to-earth rationalist Kuro Sekigahara tries to investigate and disprove a strange rumor that says that students of Kitaminami Academy can get a date with a cute demon if they stay in school after dark, he finds himself attacked by one such demon, and is rescued by a mysterious girl claiming to be in his school's Demon Hunting Club. Now thrust into a world that goes against everything he believed to be real, Sekigahara joins the mysterious club, if only to get a better understanding of how demons and hunters can exist without the wider world knowing anything about them