In the small town of Leyland, a group of thieves plan to pull off their final job and steal three million pounds from a bank. The job seems to be a success, until the alarm is tripped and the police surround the building. A standoff ensues, and the police try to negotiate a resolution before the thieves begin to kill their hostages. Things take a strange turn, however, when an eerie purple mist renders everyone unconscious. When people begin to wake up, they find that they are among only a small few who haven’t been killed and mutilated by the mist. Then, the dead return to feed on the living, forcing the surviving police, thieves and hostages to band together in bitter struggle for survival.