Nishizumi Miko is a senior high‑school student from a family of hereditary tank crews. However, she does not intend to continue the family tradition. In her childhood something happened that left a deep scar in her memory, and to avoid any connection with tanks she moved to another city and enrolled in a school that has nothing related to tanks. Unfortunately, Miko is completely unlucky: this year her school reinstates a tank‑piloting practice. The practice is optional and she can refuse it, but there is one catch: Miko is the only student in that school who has experience handling tanks, and unfortunately she is not the only one who knows this.