The alien ship has hovered over Johannesburg for more than 20 years now, damaged in some way and unable to leave. Its inhabitants -- derisively known as "prawns" -- have been brought down to the surface, and more than a million of them now live in the city's District 9, a ghetto that they are not allowed to leave.
But District 9 is getting crowded, and riots have begun to break out. The human population of Johannesburg is growing increasingly uncomfortable with the prawns' presence, and it is decided to relocate them to a new ghetto -- a concentration camp, really -- 100 miles or so outside the city.
The relocation job is turned over to a private company, Multi-National United, because hey! private contractors doing military work? What could go wrong? MNU puts Wikus van de Merwe (Sharlto Copley) in charge of the job; he's a sycophantic mid-level bureaucratic who's only risen as far as he has in the company because his father-in-law runs the place. Wikus and his fellow mercenaries tackle the job with a strange mix of cheerful friendliness and brutal force.
But a terrible accident leaves Wikus stranded in District 9 with no friends to rely on. MNU is no longer interested in him, except for the monetary value he may suddenly have; the prawns don't trust him; the Nigerian ganglords who live in District 9 are out to kill him.
And all of that is just the setup, the first 20 minutes or so of the movie. From that beginning, District 9 spins a terrifically exciting and creative story about one man's desperate attempt to survive, and his growing realization of the horrors his own society has inflicted on these outsiders.
Sharlto Copley is a marvel in the lead role. Wikus changes from incompetent buffoon to terrified outcast to unlikely terrorist, and Copley makes all of the transformations convincing, while also capturing his horror at the even deeper transformations affecting him.
The Johannesburg setting gives the movie a lot of political resonance that it might not have had if it were set in New York or Chicago. District 9 is certainly reminiscent of the apartheid-era townships; the clicking of the prawns' speech is evocative of many African click languages. (Humans and prawns have learned -- at least some of them -- to understand each others' languages, though neither is apparently capable of speaking the other.) Much of the movie is told in a mock-documentary format, with frequent cuts to cable news as the story gets more dramatic, and Blomkamp is surely commenting on the modern need to hype every story, preferably in a way that gives the audience something to be afraid of.
The special effects are superb, especially for a movie with a reported budget of only around $30 million, and every bit as good as you'd see in a Hollywood movie costing three times as much.
In its final act, District 9 becomes a relatively conventional shoot-em-up/chase/buddy movie; this is the least interesting part of the movie, and it drags on longer than it needs to. Blomkamp is also rather heavy-handed in making it clear that he's already got the sequel in mind.
But this is a smart, exciting movie that takes unexpected twists and turns. It's a thoughtful and thought-provoking popcorn flick, a fine debut from writer/director Blomkamp.