After an experimental bio-weapon is released, turning thousands into zombie-like creatures, it's up to a rag-tag group of survivors to stop the infected and those behind its release.
 
FUN FACT:  The appearance of Bruce Willis in a minor role is a subtle nod to an old marketing trick often employed by Grindhouse makers. They would contract a big-name movie star to appear in their movie for one day, for a few frontal shots only, while the rest of the scenes were done with a double filmed from the back. A picture of the big star would then be placed prominently on the movie's poster in order to boost sales. (Example: Bruce Willis' character of Lieutenant Muldoon is never in the same frame with the other actors, indicating that all of his scenes were filmed separately.) Ironically, many of Willis's later appearances in films (especially during the 2020s), such as Corrective Measures (2022) were authentic versions of this, where Willis essentially played a small part in limited scenes but was billed prominently for marketing purposes.