K’s detectives find themselves chained and trapped in separate rooms. When they manage to get out, they find Jae-suk, who explains that he survived the explosion and has since been watching over them secretly. Under the guise of Tartarus, he and K created the missions to test their ability to work as a team. Things do not go as planned when the detectives realize that Kwang-soo has disappeared with a mysterious microchip and that K has been murdered by a serial killer called the “Flower Killer”.