Co-written and directed by Park Chan-wook, this romantic crime mystery follows Hae-jun (Park Hae-il), a detective investigating a strange crime. A dead man's body has been discovered in the mountains, which has the authorities baffled. Soon, the man's wife, Seo-rae (Tang Wei), surfaces during the course of the investigation. As Hae-jun meets her, he becomes curious about her, to the point of developing a romantic interest. However, he also harbors suspicion about her role or participation in her husband's death.