Yura Yamato has just transferred to the prestigious Stella Women's Academy (ステラ女学院, Sutera Jogakuin?) and discovers that it is difficult to find friends in her first day at school. After a chance meeting with a fellow student named Rento Kirishima, she is recruited to the school's airsoft club named C3-Bu (derived from command, control, and communications, which is also the club's motto). The story revolves around Yura's experiences as a member of the C3-Bu and her interactions with her fellow members.

Stella Women's Academy, High School Division Class C3 (特例措置団体ステラ女学院高等科Ｃ３部, Tokurei Sochi Dantai Stella Jo-Gakuin Kōtō-ka Shīkyūbu?, lit. Preferential Measure Organization Stella Women's Academy, High School Division Class C3), also known by the abbreviation C3-Bu (C3部, Shīkyūbu?),[1] is an ongoing manga series written by Ikoma and illustrated by Tomomoka Midori. A television anime adaptation by Gainax began airing on July 4, 2013, and is being simulcast by Crunchyroll.

Episode 01:

"Is There No Prospective Soldier?"
"Shigan-hei wa Inai no ka~!?" (志願兵ハ居ナイノカッ!?)

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. Under the impression that the club does pretty lady things (as the rest of the academy does), Yura almost joined the club when Karila, Yachiyo, Rento and Honoka explained the club's purpose. Yura was surprised by this and left. Undeterred, Rento lured Yura to try a game with them using Yura's favorite food, cake. Yura plays a Rambo-style game with the rest of the club and discovers that she loves it. The episode ends with a cutscene showing Sonora shooting at a gun shooting range.