Throughout his youth, unskilled healer Laust was taken advantage of by unscrupulous adventurers. Despite intensive efforts to improve himself, Laust is swindled by the members of Blades of Lightning—the first party that he joins after completing his training—and is eventually banished by its leader Margulus.As the subject of public ridicule, Laust is not hopeful about his future prospects. However, novice adventurer Narsena unexpectedly offers to form a party with him, and he happily accepts. The duo quickly gain fame by conquering uncharted parts of the labyrinth. While there seems to be a reason behind Narsena's hasty proposal, Laust is oblivious to what it could be.Meanwhile, Margulus fails for the second time to slay a poisonous hydra, even after enlisting the help of elite healer Lyra for the quest. Laust soon finds himself being asked to rejoin Blades of Lightning, but it is not as easy as he imagined to move on from his former comrades-in-arms despite his new path and current companion.