After a comet causes a radiation storm on Earth, machines come to life and turn against their makers. Holed up in a North Carolina truck stop, a group of survivors must fend for themselves against a mass of homicidal trucks. A diner cook, Bill Robinson (Emilio Estevez), emerges as the unlikely leader of the pack, attempting to find an escape plan for himself and the survivors, who include his boss, Bubba Hendershot (Pat Hingle), and a newlywed couple.
When Al and Glen's parents leave town for the weekend, Al uses the opportunity to throw a party while little brother Glen and his friend Terry decide to explore a hole left by a tree-removal service in the backyard. When unexplainable phenomena begin occurring, Terry, with the help of his extensive heavy-metal music collection, comes to the conclusion that he and Glen have accidentally opened a gateway to hell.
As the son of Zeus, king of the gods, and a mortal woman, Hercules (Kellan Lutz) is blessed with extraordinary strength. Caught in a forbidden love, Hercules is exiled by his stepfather, the king, and sold into slavery. The legendary strongman endures harrowing battles and death matches in the gladiators' arena, and must use his formidable powers to fight his way back to his rightful kingdom, overthrow its traitorous ruler and restore peace to the land.