In a medieval European-inspired dark fantasy world, Guts, a ferocious young mercenary with unmatched skill, attracts the attention of Griffith, the charismatic and ambitious leader of the Band of the Hawk, a renowned mercenary group. Guts' life changes abruptly when, after a heated duel, he is defeated by Griffith and is consequently compelled to join the Hawks. Bound by a mix of respect, awe, and the complex code of honor among warriors, Guts slowly integrates into the mercenary group, engaging in brutal battles that aim to elevate Griffith's status and bring the Band of the Hawk ever closer to their dream of recognition and nobility.

As Guts begins to find his place within the Hawks, he forms a bond with Griffith that is deeper than mere camaraderie, driven by their shared aspirations and the bloody path they walk together. Meanwhile, the political landscape around them grows increasingly volatile, with the kingdom of Midland engrossed in a century-long war against the Chuder Empire. Griffith's ambitions lead him to seek a particular supernatural artifact, the Egg of the King, which promises to grant its holder the power to achieve their dreams, albeit at a grave cost. Intrigues, power struggles, and the harsh realities of medieval warfare test the bounds of Guts and Griffith's friendship, setting the stage for events that will profoundly impact their fates and the course of the war itself.