Jae Hyuk (Kim Myung-min), a clerk at a pharmaceutical company and a former doctor of medicine, was persuaded by his younger brother Jae Pil (Kim Yong-wan) to speculate in stocks a few years ago, but lost everything. Now he is a salesman for a pharmaceutical company with no prospects. He is humble and acts according to the customers' faces. He can only vent his depression to his wife and children at home. At the same time, dozens of corpses were found one after another near the Han River Basin. The bodies of the deceased were like mummies and died horribly. This incident affected a wide range of people, and even the people around Jae Hyuk were not spared. After investigation, it was found that the bodies of the deceased were all parasitic on the iron wire worms that should exist in insects. The iron wire worms would stimulate the host's appetite to absorb nutrients. When the breeding season came, the host would become unconscious, commit suicide by jumping into the water, and then enter the water to reproduce in large numbers. Faced with this new variant, humans were helpless and had no way to deal with it. The death toll increased exponentially, and South Korea was in chaos, like the end of the world. How could Jae Hyuk, who was already exhausted from running for a living, protect his family from disaster...