Every single classmate is a beautiful girl! That world is one where monsters run rampant. And the "Magic Swords" used to hunt monsters could only be wielded by women— Or so it was supposed to be. Naoto Fujiwara became the first man in history to be chosen as a partner by a "Magic Sword." What's more, he was chosen by the legendary Magic Sword, the ancestral Magic Sword 00 (Double Oh). With Naoto now studying at a Magic Sword institution filled with beautiful girls, alongside the incredibly charming heroes who wield the Magic Swords, the "Brides of the Magic Sword"— The curtain rises on a school × battle × harem story—!!