"I'm a Succubus." After school, Shun Majima, a serious and diligent boy working as a library committee member, always encounters the mysterious Mitsuya-san—an unreadable girl who keeps showing up for reasons unknown. One day, during their usual cleanup work, Mitsuya suddenly approaches him and declares that she’s actually a succubus! However… instead of the seductive allure a succubus is supposed to have, she’s completely zero sex appeal!? A chaotic, unpredictable school rom-com where a “self-proclaimed” succubus turns the life of a straight-laced boy upside down!