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.

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!