Horace possesses an extraordinary ability that allows him to remotely control countless mechanical dolls known as Golems. He single-handedly managed the entire Diamante Kingdom's public operations using this skill, working as a one-man army in the kingdom's administrative office. After the Demon King was defeated by heroes, the kingdom began dismissing commoner employees en masse. Horace is expelled from his position thanks to the actions of ignorant nobles who deem him unnecessary, freeing him from what was essentially a torture-level workload.

Far from being upset about his banishment, Horace is relieved to be free from his grueling duties. He sets off on a leisurely journey to search for rare minerals and ores to aid his research. However, his former disciples, a group of beautiful heroines who deeply admire him, refuse to let him wander alone. The first of these disciples is fully intent on building him a home under the guise of repaying his kindness, though her true motive is to keep him close. A tomboyish female alchemist also barges into his life, and Horace inadvertently attracts the attention of a troublesome eldest son from a marquis household.

Horace is an apathetic and somewhat devilish young man who rarely shows enthusiasm for anything beyond his golem research. Despite his laid-back and unshakeable demeanor, his combat prowess is overwhelming. He has a signature move of ending fights with a single, devastating punch that shows no mercy, often telling opponents to come at him so he can settle things in one blow. His disciples regard him with absolute respect, frequently exclaiming that he is worthy of being their master.

The story gradually reveals that Horace was not merely an overworked civil servant. He is the secret master of the entire hero community, the very warriors who banded together to defeat the Demon King. After his banishment, this fact comes to light, causing the kingdom's leaders to realize the immense mistake they have made. The heroes, furious at how their master was treated, demand immediate repayment of massive loans they had extended to the kingdom, loans that exceed the national budget.

As the Diamante Kingdom spirals into chaos due to its financial debts and foolish governance, Horace continues his leisurely travel fantasy focused on building the ultimate golem. The kingdom eventually begs for his return, but Horace shows no interest, having fully embraced his freedom. He finds himself in the Kaoston Dragon Stone Kingdom, where he can immerse himself in research while teaching new disciples. However, the misguided nobles from Diamante pursue him across borders, attempting to levy false charges against his party and even target Princess Lyucia, who has become one of his companions.

The narrative follows multiple perspectives, including scenes within the crumbling Diamante Kingdom and the hero community rallying to Horace's side. Key arcs include Horace battling the Spirit Heavenly Dragon Gai Giganto, conflicts with corrupt religious institutions, and dealing with the troublesome "Court Adventurer" system that evokes memories of past immigration invasion tactics that destroyed nations. Throughout his journey, Horace remains focused on his golem research while his disciples prove they can also deliver decisive one-punch justice against those who threaten their peaceful new life.