When a disease turns all of humanity into the living dead, the last man on earth becomes a reluctant vampire hunter.
Harold Gern, a shady businessman from New York, is spending a holiday in Puerto Rico with his attractive wife Evelyn. They are joined by Martin Joyce, Harold's lawyer, who has come to discuss the latest indictment. Harold invites him along on a boat trip during which all three try out some newly bought scuba diving equipment. When they resurface, they find out that the world has changed forever.
Trapped on a remote island by a hurricane, a group discover a doctor has been experimenting on creating half sized humans. Unfortunately, his experiments have also created giant shrews, who when they have run out of small animals to eat, turn on the humans.
A small town in Texas finds itself under attack from a hungry, fifty-foot-long gila monster. No longer content to forage in the desert, the giant lizard begins chopming on motorists and train passengers before descending upon the town itself. Only Chase Winstead, a quick-thinking mechanic, can save the town from being wiped out.