An eco-extremist group called The Greens invades the Cambridge Centre for Primate Research and releases from a secret laboratory a chimpanzee infected with the Rage virus. The deadly virus, transmitted through blood in seconds, leads to instantaneous infection and, upon contact with any living being, turns it into a bloodthirsty monster. 28 Days Later the entire United Kingdom is engulfed by a terrifying epidemic: many are evacuated, others seek safe places in the hope of surviving. Waking up in a hospital and having missed the peak of the epidemic and the mass evacuation, a man named Jim wanders through the empty London, trying to understand what happened. Soon he encounters the infected who attack him, but two survivors come to his aid.