Song Yong originally only wanted to have a mediocre courier career, but he didn't expect that a courier delivered in the dark of night would ignite his talent - hell. From then on, he bravely joined the "Supernatural Firm" and gathered a group of strange colleagues around him: a vicious-tongued female psychic, a contrastingly cute and strong man who exorcized ghosts, and a chatty ghost intern... While they were dealing with the client's supernatural troubles, they were also involved in a larger yin and yang imbalance crisis. In the process, weird humans and strange ghosts with their own thoughts appear frequently. While the chickens and dogs are jumping around, courage, warmth, and growth gradually appear. In the end, everyone worked together to resolve the turmoil in the underworld and complete their respective transformations, making the firm famous and creating a new possibility of harmony between monsters and the human world.
