On one noteworthy day in the Adventurer's Guild, Kazuma Satou encounters someone unexpected—a fan of his named Ran. Surprised that he even has a fan, Kazuma attempts to play it cool to impress her. Unfortunately for him, the guild's receptionist arrives with a request to defeat a giant golem guarding some ancient ruins, and Kazuma accepts only to keep Ran's admiration.

Upon Kazuma and his party's successful return from the ruins, Kazuma continues to shamelessly brag to Ran. Capitalizing on his desperation, the receptionist approaches him with another quest that requires him to return to the same ruins. Hoping to find valuable treasures, Kazuma once again convinces his party to join him—but this time, he may be biting off more than he can chew.