*Male Protagonist: Target (Cha Mu-jin) – The illegitimate son of the President of K Group, who was framed by his father’s legal wife and was sent to be imprisoned inside the closed ward. *Male Lead 2: Top Dog (Rock) – The First patient inside the closed ward. He was rumored to have been hospitalized for anger management issues, everyone assumes that he is a member of the underworld. *Male Lead 3: Black Cat (Gyeom) – A patient who was looking for a secret passage inside the closed ward. His reason for hospitalization is Obsessive-Compulsive Disorder. He suggested that he and Lee Won work together to escape from the closed ward. *Female Protagonist: Lee Won – A competent agent. She is tasked with saving the unfortunate Son of the K Group President, who is trapped inside the closed ward. She succeeded in disguising herself as a patient and entered the closed ward, only to find herself in a different world, where the rules and common sense of the outside world do not apply. *Read it when: You want to be immersed in a suspenseful/thrilling story. *Empathetic quote: “Welcome to the shithole, new guy.”