Haruhiro wakes in the dark with no memory of his life before, surrounded by strangers just as lost as he is. This manga follows the group as they step into Grimgar, a fantasy world that runs on the harsh logic of survival, and band together under Manato's lead to train as reserve soldiers alongside Yume, Ranta, Shihoru, and Moguzo. It's a story about learning to fight, and to trust each other, with almost nothing to go on.