As entrances to an alternate dimension called the "Mato" appear across Japan, a newfound resource called "Peaches" grants unique abilities exclusively to women. However, perilous monsters known as "Yomotsu Shuuki" inhabit the Mato, causing various disasters. In response, the government establishes the Anti-demon Corps, an elite group of empowered women fueled by the Peaches.
During his walk home from school, high school student Yuuki Wakura unexpectedly finds himself lost in a Mato entrance. When he calls for help, Kyouka Uzen, the chief of the Seventh Unit of the Anti-demon Corps, promptly rescues him. Recognizing his potential and the potential to enhance her Peach power, Kyouka proposes that Yuuki join the Anti-demon Corps by becoming her servant - a role he might discover to be more enjoyable than he initially anticipated.