Shiki Ryuuhou is a Monster Hunter in a world full of fantastic creatures. Before his master, Gurelli Jescar, met an untimely death, he taught Shiki the most important skill of being a Monster Hunter: teamwork.

Several years later, wielding his dual blades, Shiki heads to Akayama Town's Guild to find himself a partner. He takes a liking to the unwilling Irie Jescar, a girl notorious for rejecting any attempt at camaraderie. But her attitude soon changes; when Shiki saves her from a Rathian attack, he reveals that he has the mark of a Forbidden Hunter—meaning he is free to hunt—and that he has only one goal: to fight the legendary Miogaruna.

Irie is surprised that Shiki believes in the Miogaruna, as the only other person who believed in its existence was her late father, Gurelli. Motivated by the discovery of their shared connection, Irie and Shiki team up to fulfill Gurelli's lifelong dream. Thus, the two embark on their legendary journey, gaining allies and rivals while hunting monsters in the grand quest to find the Miogaruna.