In the mid-21st century, there is no middle class. The poor live on a polluted and diseased Earth, in which jobs are lousy and scarce, and where the police are robots who rough people up at will. And the rich live on a beautiful colony, built on a man-made satellite, Elysium, where the weather is good, houses are mansions, and every disease is instantly curable.

If some time in the future, someone wants to figure out what people in 2013 were worried about, "Elysium" will be a good place to start. It’s not a monster movie, in which all the terrors of life are rolled up into one big metaphor, nor does it express concerns about current politics or terrorism. The focus here is on one thing: what might happen if the plutocrats were to get everything they want, a world in which a small minority lives off the hardship and labor of everybody else.

‘ELYSIUM’ Rated: R Opens today

So "Elysium" is an action movie made for people thinking about something besides things blowing up. If at times the film’s connections between today’s world and the fantasy world are broadly drawn, an obvious idea is better than no idea at all. Written and directed by Neill Blomkamp, "Elysium" has a family resemblance to Blomkamp’s earlier film, "District 9," with its mix of a thoroughly realized dystopian future with an underlying social concern.

This is how bad the Earth is in 2154: Matt Damon can’t leave the house and walk down the street without someone messing with him. He plays Max, a former car thief, who lives in a hovel and works in a factory. As he waits at a bus stop one morning, a drone policeman starts questioning him, and a minute later, Max has a broken forearm. He can’t take a day off, though — no unions. So he goes to work, where he is abused by his foreman. Later, he meets his parole officer, yet another machine, who won’t let him get a word in but does encourage him to take tranquilizers.

So very quickly we get the point. Life on Earth is hardly worth living. Yet all the while, in the sky, a little closer than the moon, is the wheel-shaped paradise, Elysium, which most people will never get to visit.

Jodie Foster plays Mrs. Delacourt, the defense secretary of the Elysium colony, who could very well be French — that might be the accent Foster is going for. This is one of Foster’s best showcases in a while, a character who is Foster’s complete opposite philosophically — a heartless elitist who cares about no one — but who yet is in Foster’s general zone in terms of temperament: a smart, disciplined know-it-all, masklike in presentation, unshakable in self-belief.

Blomkamp’s cleverly constructed screenplay follows two story lines that converge. On Elysium, Delacourt is hatching a political scheme that will thrust her to the center of power. Meanwhile on Earth, a workplace accident makes it necessary for Max to get to Elysium soon, to have any hope of a cure. Blomkamp lays out the terms of this world — a citizen’s powerlessness, the unending surveillance — so that at all times the audience can feel both the seeming hopelessness of escape, as well as the desperate need to escape.

Blomkamp also provides the actors with roles they can actually inhabit and discover. As Delacourt, Foster is arresting as an evil person with many admirable, enviable qualities.

As the leader of the Los Angeles underworld, Wagner Moura gets to play, not a cliched gangster, but a mix of good and bad, a man dealing with various stresses and allegiances. It’s a rich, colorful performance, grounded in solid character writing. And, of course, there’s Damon, the actor who is always easy to overlook, because he’s always exactly what the story demands.

Damon shows you everything without trying to show you anything — at least without seeming like he’s trying. He’s like looking into clear water.