Rinko Isumi, seventeen years old. Occupation: rookie mercenary.
Rinko, who applied to a private military company thinking of it as just a part-time job, finds herself thrown into a conflict zone in a foreign country alongside Nagisa, a veteran mercenary.
In a place where she has no sense of the terrain and the language and culture are foreign to her, Rinko learns everything from Nagisa and gradually learns how to survive in this place.