Doo-hyun, who goes by the name the "Goblin", goes to prison for taking the fall for Young-min who killed their boss. Released after 10 years, Doo-hyun had been living a normal life, but Young-min goes so far as to kidnap Doo-hyun's daughter to keep his mouth shut. Enraged, Doo-hyun seeks revenge and announces the return of the real "Goblin".

Hye-jeong, a lonely young girl who has drifted away from her family and avoids personal relationships, works in a factory, lives in a shared apartment, and leads an insipid and meaningless existence until one night she discovers that she has become a ghost.

Jiwon, a motivated new police officer, is strangely bothered after meeting Osun, a social worker. On a hot summer day, a kidnapper sends a message saying, ‘If you want to save the kidnapped child, donate money to the welfare center.’ The incident becomes a national concern as the media report it. Somehow, Jiwon doubts the link between the case and Osun.