Seol Chungwon, an investigator with the Narcotics Investigation Division under the Korea Customs Service, is currently conducting an undercover operation to track down the distributors of a newly emerging drug in Korea called Pink Out. During his investigation, he encounters a man named Baek Young, who appears to be connected to the drug. Claiming he can demonstrate the drug's effects, Baek Young takes Seol Chungwon into a back room and spends time with him there. Though Seol succeeds in stalling until the police arrive, the dealers have already fled. The only remaining clue is Baek Young standing right in front of him. However, despite repeated testing, Baek Young's results come back clean every time. After much deliberation, Seol decides to bring the seemingly clueless and innocent Baek Young back to his own home. But the 21-year-old behaves like someone who has been locked away from society—displaying poor social skills and strange behavior. In order to extract information about Pink Out, Seol Chungwon begins to lure and manipulate Baek Young in various ways...