An ancient legend claims that upon the Demon God's revival, six heroes—the Braves of the Six Flowers—will be selected by the Goddess of Fate, receiving the power to resist the fiends seeking to turn the world into a living hell. Adlet Mayer, who calls himself the "Strongest Man in the World," has come to the continent of Piena hoping to become a Brave. Although things do not proceed as smoothly as he anticipated, Adlet is eventually chosen as one of the six heroes shortly after meeting Nashetania Loei Piena Augustra, the crown princess and another Brave. Rokka no Yuusha tracks the pair as they set out on their fated journey to battle the Demon God, planning to rendezvous with their fellow heroes at a small temple outside the Land of the Howling Demons, the fiends' territory. However, when they finally gather, seven heroes are present, and the others soon start to suspect Adlet is a fraud. Now fleeing, Adlet must rely on his unique skills and wit in a struggle for survival to determine which group member is the real impostor before time runs out!