Yuuki Wakura comes to a realization after leaving high school - it has been half a decade since his sister vanished during a devastating "Mato disaster." Across Japan, mysterious portals have emerged to a world called "Mato" – a demonic metropolis inhabited by calamitous monsters known as "Shuuki" that threaten mankind's safety. However, one glimmer of hope springs forth – the discovery of a Mato fruit, endowing women with supernatural powers that enable them to battle the Shuuki. This led to the establishment of a new matriarchal government, creating the Anti-Demon Corps, a female organization that relegated males to the bottom of society. Unfortunately for Yuuki, he finds himself unexpectedly thrust into Mato with no means of escape. As the Shuuki loom menacingly, a girl wearing a military uniform comes to his aid, shielding him from harm. As head of the Seventh Unit of the Anti-Demon Corps, Kyouka Uzen is a stalwart and ambitious leader, whose power was deemed an anomaly, stripping her of her peers' trust. In a life-and-death scenario, Kyouka sees this as a chance to test her abilities to their fullest potential, by utilizing Yuuki as her slave to defeat the Shuuki.