The movie opens with a series of interviews and news clips, including one with Wikus Van De Merwe (Sharlto Copley) a worker for MNU who nervously fumbles with the mic as he is being interviewed.
The history of the aliens’ arrival on Earth is told with a series of interviews and news clips. Twenty years ago a huge alien ship appears in the skies over Johannesburg and drifts to a stop and hovers over the city while the residents wait for some sort of contact, whether hostile or benign. Eventually people fly up to the ship and cut their way in. Instead of finding wondrous technology they find a dank, filthy ship filled with millions of starving, sick aliens. One scientist likens them to insects, specifically workers or drones that, after the death of their “queen” is now unable to function effectively.
The aliens are airlifted out of the ships and moved to where a temporary hospital is set up to treat them. Over time though, the temporary housing becomes permanent and District 9 becomes a slum. There is some excitement over the aliens’ technology, particularly their weapons technology and there is disappointment when it is discovered that their technology will only work with the alien DNA and is useless to humans. Despite this fact there are groups that persist in collecting the weapons, including a gang of Nigerians that are obsessed with making the weapons work. We see the leader of the Nigerians buying yet another batch of weapons and paying the desperate aliens with cans of cat food, which the aliens consider a delicacy. As the aliens leave the gang leader calls one back and as the alien asks what he wants he is struck from behind by one of the gang members. The Nigerians believe that by eating the aliens they will gain their power and be able to use the alien weaponry. Through the news clips we see how the aliens became more and more segregated and violence between humans and aliens grow increasingly frequent. According to one interview, an enduring mystery of the aliens’ arrival is when after the ship arrives new footage shows something detaching from the ship and landing. Authorities searched for the item, but never found it.
Eventually MNU (Multi-National United) a private company that has been placed in charge of District 9 is tasked with relocating the aliens to a new encampment 200 km from Johannesburg. MNU must serve all the aliens with eviction notices that give them 24 hours to prepare to be relocated. Much to his surprise Wikus is placed in charge of the relocation operation by Piet Smit (Louis Minnaar) who is in charge at MNU and is Wikus’ father-in-law. As MNU prepares to roll out, Wikus is showing a camera crew around and introducing various members of the team, it is apparent that he is fairly popular and seems to be on good terms with everyone save for members of the mercenary private security team that is accompanying the MNU team for the relocation. Wikus reprimands one of the mercenaries for bring too much ammunition and the leader of the mercenaries attacks him and gets in his face telling him it is none of his business.
As news cameras watch, the huge convey enters District 9 and Wikus jokes with a member of the MNU security team as he puts on his body armor. The next scenes are similar to an episode of Cops as Wikus goes from door to door in District 9 serving the eviction notices. Wikus is friendly with the aliens, but a little condescending and he continually refers to them as “Prawns” which is a derogatory term for the aliens. At the first house the alien angrily knocks the clipboard bearing the eviction notice from Wikus’ hand and goes back in his house. The security team seems ready to force the alien to sign, but Wikus tells them it’s not necessary as the mark left on the notice by the alien striking it counts as a signature.
As the MNU team continues to travel through District 9 you can see the horrible conditions the aliens live in. As the go through the house Wikus cheerily shows the camera crew where the aliens are hiding caches of weapons and at one shack he finds a cluster of the aliens eggs and calls in a team that destroys the shack and the eggs with a flamethrower. As the shack burns Wikus jokingly compares the popping sound the eggs make as they burst from the heat to that of popcorn.
As the MNU team continues on we see two adult aliens and a child searching through one of the heaps of garbage for something. One alien reprimands the other for bringing him some human technology stating that it is “worthless” and they need their own technology. The alien child comes up to his father and shows him a bit of alien technology that he found and asks if it will work. Excitedly the alien who we find is called Christopher Johnson, returns to a shack where he has set up an apparatus that refines some sort of fluid from the alien tech and drains it into a silver container. He tells his friend that it has taken him 20 years to collect all of the liquid in the cylinder and now it is ready. Suddenly, they hear Wikus and the MNU team approach and Christopher panics, ordering his friend to hide the cylinder and then deal with the MNU team and he will return to his son.
Christopher sneaks out the back of the shack while his friend answers the door and tries to put off the MNU team. Wikus enters the shack expecting to find another weapons cache, but to his shock, finds Christopher’s equipment, which baffles him. As he is searching for weapons, he finds the hastily hidden cylinder and as he examines it the top opens and some of the fluid within sprays him in the face. He begins coughing and hurriedly wiping his face and orders the cameraman to turn off the camera and tells him to delete the footage of him being exposed to the chemical. When the filming resumes, he makes a show of sealing the cylinder up in an evidence bag for future testing. He then goes out where the security team has Christopher’s friend in custody and begins questioning him. The alien panics and attacks throwing the security guard into the wall of the shack and hurling Wikus away and injuring his left arm. The mercenary team is called in and their leader almost gleefully kills the alien, saying he loves watching them die.
Wikus refuses to be taken to the hospital and his arm is bandaged and placed in a sling and the team continues the operation.
Christopher returns home where he meets his son who happily tells his father that he has fixed a machine that shows a hologram of the solar system. Christopher tells him to turn it off and the boy asks where his father’s friend is. Christopher tells him that his friend is gone and after the boy goes outside he angrily punches the wall.
Eventually Wikus and his team arrive at Christopher’s shack. Wikus tries to charm the young alien with candy but is angry when the alien hurls the candy back at his head. Christopher comes out and Wikus begins telling him to sign the eviction notice, but Christopher actually reads it and refuses to sign. Wikus tells him that even if Christopher refuses to leave, Wikus can declare that their living conditions are unfit and remove Christopher’s son. Christopher panics, and watches while under guard as Wikus enters the shack and is surprised at all of the computer equipment that is lining the walls of the shack. He comes out to ask what Christopher is doing with the computers when he suddenly becomes violently ill and begins vomiting.
Wikus is rushed out of District 9, but he asks that they stop at a restaurant so he can get something to eat. As he hungrily eats, his teammates ask if it’s smart for him to eat when he was throwing up not long ago. Wikus tells them he feels great, but his teammates are horrified when a black fluid begins to leak from Wikus’ nose.
They return to the MNU headquarters where Wikus sits worried at his desk when suddenly one of his fingernails falls off. He rushes to a bathroom and is horrified when another nail comes off of his fingers. He returns home, growing increasingly ill and is rushing to the bathroom when it turns out that his wife Tania (Vanessa Haywood) has organized a surprise party to celebrate his promotion. As Wikus tries to make it to the bathroom he keeps getting waylaid by well wishers and his father-in-law who angrily tells him that there were too many aliens killed that day and if Wikus can’t handle the operation he will find someone who can.
Wikus blearily blows out the candles on his cake, but when he tries to cut it, he vomits again and then passes out. He is rushed to the hospital and Tania waits worriedly as a doctor tends to Wikus, slowly unwrapping the bloody bandages on his arm. As Wikus tells him what happened the doctor unwraps Wikus’ hand and Wikus is horrified when he sees that his hand has changed into an alien hand. The doctor knocks Wikus out with gas and hits an alarm and Tania watches in horror as Wikus is placed in a body bag and forcibly removed by soldiers.
Wikus is wheeled into a lab facility where he sees scientists experimenting with alien remains. The chemical is altering his DNA and he can now operate the alien technology. He is taken to a weapons firing range and the scientists gleefully force him to test fire each of the alien weapons they have captured until Wikus refuses to cooperate. Eventually the scientists bring in a live alien and force Wikus to shoot him and the alien weapon causes the alien to bloodily explode.
Wikus is strapped to a table as a scientist tells MNU bosses (including Piet) that they need to dissect Wikus as soon as possible as no one has survived this process and Wikus is extremely valuable, but they must dissect him while he is still alive before the conversion is complete and Wikus becomes fully alien. The heads agree (including Piet) and then leave to allow the scientists to do their work.
As the main scientist announces that he will first remove Wikus’ heart, Wikus awakens fully and as he panics he manages to escape into the city.
He steals clothes and makes his way back to his house where he finds MNU people removing all of his possessions. Piet has told Tania that Wikus is dying from an infection and that she is not allowed to see him when he receives the phone call that Wikus has escaped.
Wikus enters a restaurant and tries to buy food just as a news bulletin comes on claiming that he is sick from having sex with the aliens (accompanied by a fake photo of him having sex with one of the aliens) and the crowd panics and he hastily flees.
After nearly being caught after taking a phone call from his wife, Wikus hides in the one place he knows he will be safe from MNU and the mercenaries, District 9.
Wikus continues to transform and is eventually tracked to District 9 and he hides in what turns out to be Christopher’s shack. Christopher tells him to leave, but Wikus begs him to let him hide for just 5 minutes when Wikus notices that all the stolen computers (which he thought were for decoration) are now running some sort of program. Christopher realizes what is happening to him and knocks Wikus out, telling his son to hide him under the shack.
Wikus wakes up and finds himself in the hidden drop ship, which Christopher and his son have been repairing with the intention of returning to the mother ship and using the chemical to return to their home world. He tells Wikus that if they can get to the mother ship there are machines that can return Wikus to human, but they need the fuel to power the ship. Wikus tells him that it is at MNU headquarters and retrieving it would be a suicide mission.
That night Wikus gets a call from Tania who tells him she no longer believes her father’s lies about him and Wikus tells her that he knows a way to fix himself but she can’t give up on him.
He returns to Christopher’s shack where he finds him trying to convince his son that they will be going to the new District 10 and things will be ok there. The son angrily says he wants to go to their home planet and Wikus admits to them that District 10 is not better and is “basically a concentration camp.” With little choice the two decide to go after the cylinder.
Wikus goes to the Nigerians to purchase weapons and is nearly killed when they see his transformed arm and the gang leader states his intention to eat Wikus’ arm to gain his “power.” Wikus narrowly escapes when he manages to grab an alien weapon and kill several gang members and steals several other weapons.
At MNU headquarters, Piet and the mercenary leader are discussing Wikus and the mercenary assures Piet that they are moving in to capture Wikus, but neither he nor Christopher are in the shack when the soldiers arrive.
Suddenly the entire front of the building explodes under alien weapon fire and Christopher and Wikus enter the facility. They fight their way down to the lab where Wikus had been held. Wikus finds the cylinder and calls for Christopher to leave but Christopher has discovered one of the dead aliens that the scientists had been experimenting on.
Soldiers attack them, but Wikus manages to snap Christopher out of it and Christopher grabs some spare equipment and fashions a bomb and destroys a wall allowing the duo to steal a MNU truck to return to District 9.
They arrive back at the shack and Christopher prepares for take off, but when Wikus asks him how long the reversal will take, the alien tells him that he has decided that his people come first and that he will be able to help Wikus in just three years. Wikus is furious and knocks Christopher unconscious, returning to the ship and having Christopher’s son prepare for take off.
He brushes off the boy’s concern for his father and finally manages to get the ship to lift off. As he attempts to fly away, the ship is struck by a missile, loses an engine and crashes back into District 9. Both Christopher and Wikus are taken into custody by the mercenaries and as they are being driven out of District 9, the convoy is attacked by the Nigerian gang under orders to retrieve Wikus.
Onboard the alien drop ship, Christopher’s son begins activating systems that allow him to control the mother ship and all the alien technology, which is fortuitous as he is able to remotely control a battle suit in the Nigerian compound and rescues Wikus.
As mercenaries attack the Nigerians Wikus climbs into the battle suit and leaves. Outside he sees a beaten Christopher but chooses to flee and save himself rather than save the alien. The mercenaries decide to just kill Christopher as he is refusing to talk and Wikus hears them over the suit’s audio pickups. He returns and kills the guards and tells Christopher that he needs to get back to the ship and Wikus will cover him.
They then set off with Wikus protecting Christopher and rather messily killing the mercenaries. Eventually the suit takes enough damage that it is no longer mobile and Wikus yells for Christopher to go, that he’ll hold off the soldiers. Christopher initially refuses but relents, promising to return for Wikus.
Christopher reunites with his son at the drop ship just as the mother ship moves into position above them. Christopher activates a tractor beam that begins to draw the ship up into the sky back to the mother ship.
Wikus continues to battle the soldiers, even catching a rocket fired at Christopher’s ship, but eventually the suit takes too much damage and expels him out where we see that his transformation has spread with alien skin erupting through his own and his left eye transforming into an alien eye. The mercenary leader stands over him gloating when suddenly they are surrounded by the other residents of District 9, as Wikus watches, the aliens swarm upon the mercenary and tear him to pieces as Christopher’s ship reaches the mother ship.
Wikus watches as the giant ship’s engines fire and the ship leaves Earth as the residents of Johannesburg cheer. The camera point of view switches to a newscast that states that this is the last footage of Wikus. We then see interviews with Wikus’ family where they say that they believe he is dead, and one scientist states that no on knows if Christopher is just escaping, or if he will return with an army. We also see that the rest of the aliens were successfully relocated to District 10.
The movie ends with an interview with Tania who earlier had told the interviewer how Wikus would make her homemade presents. She had found a flower sculpted out of scrap metal on her front porch that she believes that Wikus had left her, despite her friends’ assertions that he is dead.
In the final shot we see an alien sitting and sculpting another flower, implying that Wikus completed his transformation into an alien and is living among them.
You can send in your spoiler to other movies by going here.