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- !?