Saitou is an ordinary, perpetually overlooked handyman in modern Japan whose mundane skills—unlocking doors, replacing lightbulbs, and tightening screws—leave him feeling utterly useless. His life dramatically shifts when a speeding truck reincarnates him into a fantasy realm. Devoid of magical powers, legendary swords, or heroic stats, Saitou quickly discovers that his seemingly boring toolkit makes him an indispensable asset to a chaotic, ragtag adventuring party.He joins forces with Raelza, a skilled but deeply insecure female warrior obsessed with Saitou's gentle validation; Morlock, a brilliant yet senile wizard who frequently forgets his incantations mid-battle; and Lafanpan, a greedy, cynical fairy priestess motivated entirely by financial gain. Together, they navigate treacherous dungeons, battling goblins, demons, and undead horrors. Saitou’s utilitarian expertise—using crowbars to spring traps, duct tape to patch armor, and screwdrivers to dismantle magical constructs—saves the party from certain doom repeatedly.As they delve deeper into the labyrinthine depths, the overarching plot expands beyond simple
dungeon crawling. The narrative weaves in the tragic backstories of various eccentric adventurers populating the realm, including a former hero corrupted by time and a powerful demon king dealing with
political turmoil. Saitou acts as the emotional anchor for this dysfunctional community, forging deep bonds of trust and romance, particularly with Raelza, whose affection for him grows as he continuously proves his worth without ever wielding a blade.However, danger escalates when the party encounters a massive, city-threatening labyrinth boss and a sinister conspiracy involving the kingdom’s nobility. Saitou faces his ultimate test when he is separated from his companions and forced to rely solely on his wits and his remaining tools to survive against overwhelming magical onslaughts. During this harrowing trial, Saitou grapples with his identity, realizing that his ordinary humanity is not a weakness, but a unique power in a world obsessed with grandiose magic.The climax culminates in a desperate, coordinated battle where Saitou uses every trick he has ever learned—along with the synchronized efforts of his loyal friends—to defeat the dungeon's master and foil the political plot. Ultimately, Saitou finds the profound sense of purpose and belonging he always craved, proving that even the most unremarkable handyman can become an irreplaceable hero when he uses his skills to protect the people he loves.