Stella Women's Academy, High School Division Class C3

Yura Yamato is a shy girl who enrolls in Stella Women's Academy. On her first day at the academy, she checks into her dorm to find that her roommate, third year Sonora Kashima is out visiting her family. Looking around the room, she discovers her roommate's collection of military items, such as guns, action guerilla movies etc. At the same time, the C3 Club meets elsewhere in school to discuss the recruitment of new students into the club. After coming up with a ridiculous plan and deciding that it would be unrealistic, they decided to take a break and play a Rambo-style battle to lighten the mood. Rento goes to Yura and Sonora's room to borrow Sonora's M60 and unexpectedly stumbles onto Yura playing with the "props" while watching Rambo. Deciding that yura fulfilled the condition to be recruited, she brought Yura to the C3 Club.

Yura finally meets Sonora, who had returned from a shooting contest in America and becomes impressed by her skills at making onigiri, reminding her of her own marksmen training. Revealing herself to be the president of the C3 Club, Sonora asks Yura if she wants to officially join, but Yura doesn't have enough confidence to agree. Meanwhile, the other members try their own hair-brained schemes to get Yura to join, with little success. Becoming impatient and not giving Yura time to give an honest reply, the members challenge Yura and Sonora to an escort match, in which Yura must safely escort an unarmed Sonora, stating that if they lose, Yura will be forced to join the club. Sonora manages to take Yachiyo down with her own weapon whilst Yura manages to use a clever rouse to get Rento and Honoka to take each other out. As Yura becomes nervous about facing Karila, Sonora tells her to think of her gun as an onigiri and together they manage to take down Karila.

The girls enter a national high-school airsoft tournament, which follows capture the flag rules. The girls manage to win the first round after Yura grabs the opponent's flag and the team continue their winning streak all the way to the finals. There, they are to face Meisei Girl's Academy, who they've always drawn against on previous encounters, one of their member's being Rin Harada, who was Sonora's partner in America. As the match gets underway, Meisei prove to be tough opponents, as they manage to take out the majority of Stella's team, with only Yura remaining. Yura becomes more panicked when she overhears Rin being more focused on taking down every member instead of just stealing their flag and decides to forfeit out of fear. Afterwards, Rin scolds Yura for her cowardess, with Sonora sharing the sentiment. As Yura ponders over her actions, she realizes that if she wants to change, she'll have to make the changes herself.