A group of people are trapped in a deserted mall during a flood along with an escaped prisoner.

In 1979, a delivery truck makes its way up a lonely southern California highway in a storm, bound for the San Diego Zoo with a deadly tropical rattlesnake as cargo. When the truck suffers a blowout, the driver loses control and hits a tree, shattering the snake's aquarium in the back and the window separating the snake from the driver. The snake slithers into the front of the truck, kills the driver with its bite and then moves off into the forest. Flash forward to 1999. The small southern California town of San Vicente has grown from 6,000 to 30,000, and the rattler, which escaped nearby years ago, has bred. There are now 25,000 of these hybrid rattlesnakes, and they are slowly making their way downhill into the town, attracted by the movement of the blasting as the town paves its way toward progress. Progress, in this case, brings terror, in this tale originally penned by John Carpenter.

Right after Disneyland opens in Anaheim, California, in 1955, a toy salesman in town for a convention brings his wife with him so they can both go to Disneyland. They stay at a rundown place called the Sunset Motel nearby. Soon the wife is having an affair with a man staying at the motel. The husband hires a psychotic criminal to spy on them, the wife and her lover plan to murder the husband, and the voyeuristic motel manager is spying on everybody.