After defeating Sylvia at the Crimson Demon Village, Kazuma and his party look forward to receiving a reward that could mean freedom from the grind of having to fulfill quests. Kazuma himself, however, seems to be having nightmares and bouts of paranoia.

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.

Darkness departs the mansion leaving behind a note. Not satisfied by a single note, Kazuma, Aqua, and Megumin protest in front of the Dustiness manor but are rudely turned away. Kazuma, frustrated with everything, is approached by Dust who needs his help.

Darkness's wedding to Aldarp is imminent. Despite Aqua's and Megumin's pleas, Kazuma has no intention of intervening. Vanir then visits the mansion and reveals a shocking secret to Kazuma.