Tiago, a so-called "Beastmaster," is completely incapable of taming even a single monster. Labeled as a failure, he serves as nothing more than a glorified errand boy in the adventurer party led by his childhood friend. One fateful day, while exploring a dungeon, the party encounters the legendary beast Fenrir. Seeing no other way to escape, they abandon Tiago as bait. Just when he’s about to give up on everything… he miraculously tames Fenrir! Despite being an SSS-rank mythical beast, the powerful Fenrir acts surprisingly human. Amused by his new companion, Tiago names him Ginta. From that moment on, Tiago embarks on a carefree journey of adventure, encountering legendary holy beasts and discovering a power within himself that no one ever expected!