Akito, an adventurer belonging to the party “Golden Fang,” has always contributed by using his Extra Skill [Unlock & Lock] to open his comrades’ skill trees—allowing them to acquire new abilities. However, due to his low combat ability, he is expelled from the party. Left behind inside the labyrinth, Akito uses [Unlock & Lock] on himself, releasing his own sealed skills. With his true power finally awakened, he begins his attempt to escape the dungeon… and thus the door to this wildly popular “strongest” fantasy adventure opens!