Chris tells Kazuma that the necklace he and Iris swapped bodies with is a sacred treasure, and it is dangerous and can threaten lives depending on its use. Princess Iris is in danger! Two robbers dressed in black sneak into the royal castle at night!
Kazuma and his friends attempt to defeat Coulomb's Hydra but fail due to low-level adventurers, a bandit spree, and a bounty. However, for some reason, Darkness insists on defeating the Hydra.
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.
Kazuma thinks of a way to stay in the capital for Iris's sake, and declares that he will capture the thief who's causing a stir in the streets! Since the thief targets nobles with bad behavior, Kazuma and his friends decide to stay at Alderp's mansion.
Kazuma and his friends return to Axel and receive 300 million eris as a reward for subjugating Sylvia, an executive of the Devil King's army. Kazuma and Aqua go to high-end restaurants, and Aqua enjoys her long-awaited life as a celebrity.