Fleeing a traumatic childhood, lone mercenary Guts drifts from battle to battle, striking down powerful enemies with his unwieldy sword. After one skirmish, Guts clashes with the mystifying Griffith and his small army known as the Band of the Hawk. The victorious Griffith drafts Guts into his ranks, granting the swordsman a kinship unlike anything he has ever known. Alongside the skilled warrior Casca, Guts helps Griffith guide the band to fame and glory. But as he gains military prestige, Griffith becomes the target of assassination attempts and political schemes. He uses Guts to further his ambitious rise to power, taking advantage of the swordsman's lack of aspiration. Even as he grows closer to Casca, Guts' absence of direction robs him of any sense of belonging. Fostering opposing desires, Guts and Casca fight for Griffith's dream—although fractures forming among the trio threaten to disrupt their world.

The streets of Treasure Town are said to belong to "The Cats." They know everything that goes on in the city, and no one can stir up trouble without going through them first. In reality, The Cats are a pair of orphan boys called Black and White, who aren’t afraid of anything or anyone. But their rule of the streets is challenged when the Yakuza come to town and start making changes. The wild Black and the carefree White have no one to rely on but themselves to get their Treasure Town back to the way it was. But their bond is tested as they quickly realize going back to how things were may no longer be an option.