Six transfer students arrive at the same high school on the same day. After classes, they gather at a karaoke bar, appearing to be typical girls enjoying their youth. In reality, their conversation is a strategy meeting to prevent a school bombing. A terrorist organization known as the Yamato Liberation Front is secretly planning to attack the school, and to counter this threat, a special force of high school girls called the Duffle Coat Army is activated.

The story is set in an alternate version of Japan that has been divided into East and West by the Cold War. The Duffle Coat Army is deployed on a mission to unify the country by rescuing a key individual. However, the operation goes wrong deep within enemy territory, leaving the team isolated. They must now embark on a 700-kilometer逃亡剧 (running battle) to reach the border at the 138th meridian east.

The main characters are the six girls who make up this special unit. While they are highly skilled operatives, their personalities also reflect their age, bringing moments of comedy and青春 (youthful) naivety to the high-stakes narrative. The series blends intense gun action, drawn with precise detail, with elements of a road movie as the characters travel through real-world locations in Hokkaido and the Tohoku region. Along their perilous journey, the girls also encounter local gourmet foods and scenic landscapes, providing brief moments of respite. One of the first major narrative arcs involves a plot to bomb their school, which serves as the catalyst for their deployment. The story then shifts focus to the long-term mission of transporting a VIP designated as the "King of Heaven" across hostile territory to safety, with the fate of the Duffle Coat Army members becoming clear within the first volume.