At a small county jail outside Las Vegas, a prisoner makes his way to an appeal hearing. Taylor watches for any opportunity at escape left open, never expecting what does free him: a full-scale alien invasion that leaves the entire United States in ruins.

Eleven months later, some of the last men and women hide below a bridge on the outskirts of the city. The aliens have eliminated most of the population, leaving solitary sentinels to roam the skies and shoot down survivors. Using a battery powered radio, Melanie, a former community college poetry teacher, and Twink, a displaced nuclear engineer, discover the aliens have returned to their homeland for reinforcements. What is left of the human race is assembling in preserves to breed an army for their return.

The preserves are not unfriendly, but their morality is all wrong. There is no monogamy, mothers are discouraged from spending too much time with their babies, and the leader, a former talk-show host, parades around like a self-appointed God. Even more disturbing, a sentinel watches over the preserve, but does not attack. Taylor, Melanie, Twink, and Joey, a witty homosexual trying his best to look ‘like a breeder,’ band together to discover the secrets of the preserve.

After what appears to be a U.N. Assault on the sentinel turns out to be a futile freeing of the preserve, the group decides it’s best to move on and fend for themselves. Why would the United Nations be trying to ‘free’ them? However, the sentinel does seem to fire upon would be escapees and they are left to try to find another way out.

Further investigation reveals the babies being feed some sort of nutritional supplement that makes them docile, a small ship traveling to and from the sentinel above, and a whole lot of people working at the hydro plant who have no idea how to operate a hydro plant. They confront the leader, General Gervin, who, with his life on the line, admits he ‘made a deal’ with the aliens, who are desperately afraid of us and our germs – the nutrient supplement is a sort of internal disinfectant. He proposes a plan, a trip up to the sentinel to expose the aliens to their germs and to get message back to their homeworld that Earth is unsuitable for life. If that doesn’t work, they can at least blow up the sentinel.