Shy high school girl Koharu stops by a mysterious antique shop one day and buys a model kit. To her surprise, she is swept into the mysterious parallel world of the Girl Gun Fight... where only the surviving team can escape.

Koahru's friends Natsuna and Akiho teach her the rules of Girl Gun Fight as she is again drawn back into the parallel world for the next battle...

Koharu (Sei Shiraishi), who thought that this was not a game but a murderer, had a gun after Mizuno (Manami Igashira), who was "Rasuichi", was shot dead in a parallel world and disappeared from the real world. I was scared of that. On the other hand, the Bravo Tango, Matsuko of new student council president on behalf of the Mizuno (Anna Ishii) is, will want to participate as a player, to invoke besides commander of Bianca (Teramoto Rio), began instructs ... !? Also , Koharu learns that Natsuna (Momoka Ito) is also "Rasuichi" and takes Alice (Yuno Ohara) a more powerful gun "Blast Girl Gun" to prevent Natsuna from dying. Propose a strategy to go to. On the other hand, the speculations of each team overlapped, and a fierce competition began- !?

Koharu (Sei Shiraishi) suggested to Matsuko (Anna Ishii), "Why don't you stop killing each other?" Promising not to follow the instructions of commander Alice (Yuno Ohara), and getting consent with certain conditions. And in the real world, Charlie Tango's Ichika (Azusa Ohara) and Futaba (Rina Kannan), Megumi Mitsu (Hina), Kitamoto (Ai Mikami), Minami (Aoi Uta), and Higashino (Momoko Tanabe) of Delta Tango. Koharu, who approached the story, succeeds in promising each other that they will not kill each other in "Girl Gun Fight". When the Girl Gun Fight begins, Alice notices the light bullets that the players miss and the strange atmosphere ...!? On the other hand, the players gather in the classroom despite the fight and have a "commemorative party where no one dies". Start with…!?

Koharu (Sei Shiraishi) was told by Matsuko (Anna Ishii) "Don't trust the Girl Gun Lady", but Alice (Yuno Ohara) was a player of Alpha Tango in the past, Masami (Tomi). I will be told the story. The photo at that time on the album shows a battle method called "Plamode" that is unfamiliar to me, and when the girl gun lady and the player's hearts are united, Natsuna (Momoka Ito) activates it. Koharu hears from Akiho (Natsuki Deguchi) ... On the other hand, Koharu is confused when he is consulted by the enemy team, Higashino (Momoko Tanabe) of Delta Tango, as "Rasuichi". Then, in the "Girl Gun Fight" that was greeted, while covering Natsuna of "Rasuichi", Kitamoto (Ai Mikami) and Higashino of Delta Tango chased after Alpha Tango, a strategy to get the flag, and it was extinct. In a desperate situation- !?

Koharu (Sei Shiraishi) heard from a health teacher, Moriyama (Masanari Wada), that there is a warehouse behind a mysterious antique shop. After consulting with Akiho (Natsuki Deguchi), she secretly infiltrates Natsuna (Momoka Ito), who is preparing for the national athletics competition. The two of them sneaked into the store, but as expected, the store manager (Gaku Hamada) found out, and the homeroom teacher Hoshimiya (Aya Asahina) also reported and apologized. The two thought that the secret of the Girl Gun Lady was in the warehouse, and suggested to Natsuna, "Let's break into the Girl Gun Fight." Then, I talk to Alice (Yuno Ohara) in a parallel world, but I can't find a way to open the "bilibili wall" that surrounds the school ... On the other hand, Matsuko (Anna Ishii) is not the commander Bianca (Rio Teramoto) of Bravo Tango, but for some reason Alice offers a consultation- !?

Koharu (Sei Shiraishi) and Akiho (Natsuki Deguchi) finally infiltrated the warehouse of an antique shop run by a mysterious store manager (Gaku Hamada). Inside, it was as wide as a spaceship, and it was a strange space where the players who died in "Girl Gun Fight" were lined up like stuffed animals. A light bullet was fired from behind Koharu and Akiho, who were angry, and Matsuko (Anna Ishii) was there. And Alice (Yuno Ohara) makes a certain decision ... Also, in the real world, the existence of Natsuna (Momoka Ito) was erased, and a sad reality awaited. Koharu goes to see the store manager with Akiho to check the warehouse, but the store's warehouse is just a storeroom, and the mystery only deepens. On the other hand, in the parallel world, a new player will be added to Alpha Tango in place of Natsuna- !?

Koharu (Sei Shiraishi) and Akiho (Natsuki Deguchi) teach Natsuna's younger sister Fuyumi (Momoka Ito) about "Girl Gun Fight". In order for Alice (Yuno Ohara) to become a human being and the entire team to survive, it was inevitable to win all the remaining fights and win the championship. Koharu had become "Rasuichi", but decided to fight with all his heart for Alice. And the final battle of fate finally begins. While the bloody battle is taking place, Matsuko (Anna Ishii) shoots two blast girl guns in rapid succession and hunts down Koharu ...!? And there is a change in Fuyumi who was afraid of the gun.

Matsuko (Anna Ishii) was a girl gun lady ... Matsuko, who won the past "Girl Gun Fight" and became a human from a commander on a sunny day, had a completely unknown memory in the new world. Matsuko, who confessed everything, offers to find a plastic model "Girl Armor" that can destroy the girl gun system for the surviving players before the "final ceremony". Koharu et al. Suspect that Moriyama-sensei (Masanari Wada) is M Taro who made "Girl Armor", and with the cooperation of Hoshimiya-sensei (Aya Asahina), try to find out ...?

Everything became clear. The store manager (Gaku Hamada) created the "Girl Gun System" world by purchasing the "Girl Gun Lady" created by the legendary modeler M Taro. Finally, the ceremony for Alice (Yuno Ohara) to become a human begins, but Koharu (Sei Shiraishi), Akiho (Natsuki Deguchi), and Fuyumi (Momoka Ito) are also restrained by mysterious power and can't move ...! Can Alice become a human being, and can Koharu and his friends live and return to their original world? The last of the shock is clear ...