When former LAPD officer Brett Anderson takes a job as head of security at an old apartment building in Sofia, Bulgaria, he soon begins to experience a series of bizarre and terrifying events. Soon after delving into the building's sinister history and investigate its shadowy owners and past employees, Brett uncovers a malevolent force nestled deep in the bowels of the building that will do anything to be set free into our world.

A police-escorted prisoner transport supervised by Interpol sets off to Belgrade. The route leads the transport through Pančevo, where they encounter an ecological disaster and infected people who are trying to kill them. Interpol agents Mortimer Reyes and Mina Milius soon realize that their only chance for escape from the zombie hordes lies in allying with the dangerous, mysterious prisoner.