It's the year 3000, Earth has been ravished and nearly all of mankind has been exterminated by a vicious alien race known as the Psychlos. Nonetheless, small tribes of what have essentially become primitive humans have survived outside the now long since decimated urban centers. In one such tribe, a hunter, Jonnie Goodboy Tyler (BARRY PEPPER), doesn't believe in the mythology supported by the others and thinks that there has to be a better life somewhere out there in the world. As such, he leaves his mate, Chrissie (SABINE KARSENTI), and sets out to find it.
Instead, Jonnie and another man, Carlo (KIM COATES), are captured by the Psychlos in an ancient city and transported to the human processing center in the Dome, a large structure inhabited by the alien race. There, he discovers that the Psychlos have captured many other humans and use them as slave labor. He also eventually meets Terl (JOHN TRAVOLTA), the corrupt Chief of Security who's happy to be getting off what he considers a miserable excuse for a planet and handing the post over to his assistant, Ker (FOREST WHITAKER).
Unbeknownst to Terl, who has a knack for blackmailing most everyone he knows, he's been ordered to stay on Earth for another fifty cycles, something that angers him to no end. In response, Terl decides to get his revenge on his superiors by not reporting Ker's earlier discovery of gold veins in the Rocky Mountains and instead hoarding the valuable metal for himself.
Of course, he needs to keep his plan secret from District Manager Zete (MICHAEL MICREA) and thus decides to use human, and not Psychlo laborers to mine the ore. Believing most humans to be nothing more than animals, Terl handpicks a select few he wishes to educate and thus enable them to operate the related machinery.
Little does he know, however, that by educating Jonnie, he's setting into motion a series of events that will forever change life on Earth. From that point on, it becomes a battle of wills and smarts between Terl and Jonnie as each tries to achieve what's best for themselves.