Naryecheong, a secret state organization that protects humans from incidents and disasters caused by evil spirits. Yoon Taehee, a senior Naja in Naryecheong, is searching for a ‘gwijae’—someone who has the ability to see and hear ghosts—to recruit as a new member. One day, while on a mission and concealing his identity, Yoon Taehee encounters a suspicious boy at a high school in the small town he visits. ‘By the way, friend, how old are you?