As a result of a magic circle that Aqua had drawn in Keele's dungeon, strange explosive doll monsters have started to appear, putting the town at risk.

After returning from his trip to Arcanretia, Kazuma is living life without a care in the world, thanks to his debts being all paid off by the reward money he earned from eliminating one of the Devil King's generals, Hans. One day, a rookie adventurer named Ran comes up to him in the Guild Hall asking for a handshake. She's apparently become a fan of Kazuma after his consecutive defeat of the Devil King's generals! This puts him in an amazing mood, but it's not long before the Guild receptionist Luna appears, asking him to take on a quest to eliminate a golem. Wanting to look good in front of a fan, Kazuma ends up accepting, and heads towards ancient ruins with Aqua, Megumin, and Darkness in tow.

The Devil King's army attack alarm rings in the royal capital! The adventurer's guild calls on high-level adventurers to join the battle. Having failed to capture the thief at Alderp's mansion, Kazuma joins the fight in order to redeem his reputation.