In the remote forest village of Gokseong, terrible things are happening — people are suddenly covered with sores, behaving strangely, and even attacking their own relatives. Several murders have already taken place. The police are at a loss. Rumor has it that some poisonous mushrooms or a visiting Japanese man are to blame. Local policeman Jong-goo looks at what is happening rather aloof, but not until his daughter is caught up in the nightmare.