After decades of anarchy and dark times humanity regains its nation and civilization, but science, technology and cultural maturity return to basic levels.
It's 50 years after the start of the "New World history", but Japan still has war with "Continental Union". Situation reaches stalemate after two years of active action, and only technological innovation can cause a breakthrough.
Main character is appointed as platoon leader of the new weapons experimental unit. The subordinates are five amateur soldiers who are all women. The mission is to spread the new weapons technology with province regions, oppose guerrilla forces and get the real picture of the battlefield spots. Protagonist has unlimited authority over his team, and it's up to him whether he brings up soldiers in spartan conditions or harasses his subordinates to satisfy own desires.

[From vndbreview]