Jae-hyuk is a pharmaceutical worker for a medical supplies company. When a series of dead bodies are found floating in the Han River. The public is shocked to discovered that the deaths are related to a fatal outbreak of virus-infected mutant parasitic horsehair worms, called ‘Yeongasi’, that can control the human brain. Those infected shows symptoms of hunger and thirst, hence jumps into the river to combat dehydration. Whilst the authorities work to find a cure, Jae-hyuk struggles to save his family when they also exhibits similar symptoms.

I Saw the Devil

Kyung-chul (Choi Min-sik) is a dangerous psychopath who kills for pleasure. He has committed infernal serial murders in diabolic ways that one cannot even imagine and his victims range from young women to even children. The police have chased him for a long time, but were unable to catch him. One day, Joo-yeon, daughter of a retired police chief becomes his prey and is found dead in a horrific state. Her fiance Soo-hyun (Lee Byung-hun), a top secret agent, decides to track down the murderer himself. He promises himself that he will do everything in his power to take bloody vengeance against the killer, even if it means that he must become a monster himself to get this monstrous and inhumane killer.