They exterminated most of us humans, but they've kept some as prisoners. And there are pockets of survivors living in the hills and woods, eking out a primitive existence of the savage variety. This is the film version of the first half of L. Ron Hubbard's hugely popular science fiction novel from 1982. Barry Pepper is Jonnie, a courageous, angry, and resourceful man living in the woods, among other human survivors.
Problem is, they're lacking in food.
He teams up with a couple other folks that he meets along the way. Meanwhile there's John Travolta, as Terl, the head of security here on earth. The Psychlos are mining the bejeepers out of earth, depleting it of its resources. It's Terl's job to babysit the colony and make sure everything's operating smoothly. He hates his job and is looking forward to reassignment.