The movie tells the story of a disaster caused by a parasite called "wireworm". In the movie, the worm can control human consciousness and kill people by parasitizing and reproducing inside the human body, and its reproduction rate increases rapidly when it comes into contact with water, and people who are infected by the worm commit suicide by jumping into the river. The national emergency mechanism is quickly activated, and all the infected are quarantined, but the crisis is still imminent. Jae-hyuk, a salesman at a pharmaceutical company, whose wife and son are also infected by the nematode, tries to find a cure in order to save his wife and son's lives. As the nation is gripped by the devastating disaster, the Han River is filled with mutilated corpses. ......