I want to become an Incubus, too!

During the summer of 202X, a problem arises for many demons who have been collecting human souls to replenish their mana. With an abundance of devilish humans compared to demons, there is little need to seek assistance from demons, even when trading their souls. To address this employment challenge, demons are looking to transition to a 'mongma' that can gather energy without needing human consent. Uffir faces the same situation, but the process proves to be more complicated than anticipated. Ultimately, a detective named Cheol-ho confronts Uffir, who is attempting to become a mongma by deceiving him.