Yoshino Takigawa, an ordinary teenager, is secretly dating his best friend Mahiro Fuwa's younger sister, Aika. But when Aika mysteriously dies, Mahiro disappears, vowing to find the one responsible and make them pay for murdering his beloved sister. Yoshino continues his life as usual and has not heard from Mahiro in a month—until he is confronted by a strange girl who holds him at gunpoint, and his best friend arrives in the nick of time to save him. Yoshino learns that Mahiro has enlisted the help of a witch named Hakaze Kusaribe to find Aika's killer. However, the witch has been banished to a deserted island due to infighting within her clan. Hakaze's brother, Samon, selfishly desires to make use of the Tree of Exodus' power, in spite of both his sister's opposition and the impending peril to the world. With Hakaze out of the picture, it is now up to Yoshino and Mahiro to help her save the world, all while inching ever closer to the truth behind Aika's death.

The Band of the Hawk and their enigmatic leader Griffith continue winning battle after battle as their prestige throughout the kingdom of Midland grows. But their latest task is one that has seen failure from everyone who has attempted it: the subjugation of the impenetrable fortress of Doldrey. But with members like Guts—the captain of the Hawks' raiders who can easily fell 100 men with his gigantic sword—such tasks prove to be trivial. However, in the aftermath of the battle, Guts decides to leave the Hawks in order to pursue his own dream and bids farewell to his companions, despite Griffith's attempts to make him stay. This single event causes Griffith to lose his composure, and leads him to make a decision that will alter his and the Hawks' fates forever.

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 Band of the Hawk has dwindled in the year since Guts left them on his journey to forge his own destiny. Unaware of their fate, Guts returns to the Hawks—now being led by his former ally Casca—after a rumor about them passes his way. Once the saviors of the kingdom of Midland, the Band of the Hawk are now hunted as they desperately fight for their lives while plotting to free their leader, Griffith, after he was imprisoned for committing treason. But the man they save is far from the Griffith they remember. Griffith is a shell of his former charismatic self after a year of continuous, horrific torture. No longer able to walk, speak, or even hold a sword, he has nothing but the small, strange trinket, the Crimson Behelit, that will not leave him. The entire Band of the Hawk want to rise to greatness once more, but how much are they willing to sacrifice to return to their past glory? It doesn't seem possible, but when Griffith's heart darkens and a solar eclipse blackens the sky, the Behelit offers a choice that will leave the Band of the Hawk with a blood-soaked fate that will haunt them for the rest of their days.