Set in a near-future Japan after its society became completely dominated by women due to the rampancy of radical feminists and the country introducing the "Gender Segregation Act" decades ago, you are Katagiri Yui, originally a child soldier in the defense forces who eventually got to hid in a remote village under a fake identity, who is ordered by Mother, an social management AI, to attend the training school of the Security Force, a women's armed forces with your adoptive sister.

――Spring 21XX.

Due to the rampancy of radical feminists, Japan had become a society completely dominated by women. In accordance with the "Gender Segregation Act," established a few decades ago, immediately after birth, boys were sent to concentration camps, and raised as soldiers to deal with an ongoing war. Savage men were eliminated, the world had truly become a society of women, by the women, and for the women, a Utopia of Maidens!

However, in such a world, there was one boy who tried to survive while hiding his gender. Originally a child soldier in the defense forces, because of certain circumstances, he hid himself in a remote village under a fake identity, and lived peacefully with his adoptive mother and sister.

Our story begins when the boy is ordered, under the instruction of a social management AI, the "Mother," to attend the training school of the "Security Force," a women's armed forces.

Along with his sister who decides to come with him, the boy sees the city for the first time, a decaying, yet gorgeous garden of maidens. While hiding his true identity, he attends a girls' school attached to the Security Force's headquarters, when he is assigned to live in a dormitory, he meets a kindhearted girl named "Akari." Also blessed with several senpai, during his strict, yet enjoyable training, the boy gradually befriends the girl, even develops feelings for her.

But the reality remains, there is still the fact that this world is harsh on men. A society where the extremists​ are demanding the extinction of men. If his identity is somehow revealed, there is no telling what will happen. In fact, even the girl who should have been kindhearted, cheerfully declares.

"My dream, to eliminate all the men!"