When a peaceful colony on the edge of a galaxy finds itself threatened by the armies of a tyrannical ruling force, Kora (Sofia Boutella), a mysterious stranger living among the villagers, becomes their best hope for survival. Tasked with finding trained fighters who will unite with her in making an impossible stand against the Mother World, Kora assembles a small band of warriors — outsiders, insurgents, peasants and orphans of war from different worlds who share a common need for redemption and revenge.

As the shadow of an entire Realm bears down on the unlikeliest of moons, a battle over the fate of a galaxy is waged, and in the process, a new army of heroes is formed.