The zombie plague has been around for a while now and the remaining humans have created new smaller settlements. In Pittsburgh using 2 rivers as a barrier and an electric fence as a third barrier people have a enclosed life, safe from the zombies.
Most of the people live in squalor but the rich live in a fancy high rise.
The leader of the settlement Paul Kaufman (Dennis Hopper) has a group of people go out into the zombie infected zones looking for food and supplies in a large all terrain vehicle.
Riley (Simon Baker) and Charlie (Robert Joy) have been leading the supply runs but are quitting. Cholo (John Leguizamo) is also part of the group but has been saving up to buy his way into the sky rise.
When Kaufman refuses to let Cholo in, Cholo steals the all terrain vehicle and threatens to blow up the settlement. Kaufman forces Riley to go stop Cholo.
Meanwhile the zombies have slowly started gaining intelligence and amass a large group to attack the settlement.
George A. Romero created the modern zombie movie and after a long break after Day of the Dead returned to the genre with this film.