Spunky, athletic high school student Mano Yohko doesn't know it yet, but she's #107 in a long and venerable line of demon hunters! But after her school principal sics a monster on her in the swimming pool and she's nearly seduced by a possessed classmate, her grandmother decides it's time to bring her up in true "Mamono Hunter" style! And just in time, since it turns out that a monstrously powerful demon queen is preparing to smash her way from the next world into this one!