NOTE: This spoiler was submitted by Mike.
Johannesburg is the first city to use a robot police force. Created by Deon Wilson (Dev Patel) these robots are completely automated and have artificial intelligence. Deon’s office rival Vincent Moore (Hugh Jackman) has created The Moose (basically ED-209 from Robocop), which is operated via a human. Moore isn’t a big fan of Deon’s work.
Robocop unit 22 is back in the shop again. It seems this particular unit is accident prone and always getting serviced. The techs get it back into action and send it out into the field where it assists in a police raid on a drug deal gone bad.
On one side of the drug deal are Die Antwoord’s Ninja and Yolandi playing characters named Ninja and Yolandi. They’re teamed with Amerika (Jose Pablo Cantillo). They’re trying to deliver goods to crime boss Hippo (Brandon Auret). Ninja, Yolandi and Amerika manage to escape during the police raid. Hippo shoots a rocket launcher into 22’s chest and also manages to evade the cops.
Back at the shop, the techs see that 22’s battery is fused with his chest piece, so he’s basically beyond repair. They set him aside to be scrapped.
Hippo calls the gang and tells them that he’s not in jail and he still expects them to pay him the money they owe him from their previous botched job.
Moore asks robo-boss Michelle Bradley (Sigourney Weaver) for more money to assist with further developing his Moose. Deon’s robocops are such a hit that the government has decided to sink more money into that project and has no interest in the Moose. It’s big, expensive and ugly.
Deon goes home and starts working on his newest project which is creating an artificial consciousness. After a long night of programming and Red Bull, he succeeds.
Yolandi has a plan that the robocops must be like a television so all they need is a remote control to turn them off. They look at the news and see that Deon is the dude who created the robocops, so he must be the guy who knows how to power them down.
Deon asks Bradley if he can use his artificial consciousness program on the scrapped 22 unit. He explains that it’s possible that this could create a robot smarter than humans and it could even conceivably write poetry. She explains that they’re in the business of defense and not in the business of creating poets, so she gives him the big old thumbs down.
Deon decides to take a chance, gets the scrapped 22 and the Guard Key, which is needed to update the programming in all the robots as a precaution against hackers, and smuggles them out of the factory. The gang kidnaps him before he can get home.
The gang takes Deon back to their base and ask him how to shut down the robocops. He says it’s impossible. They’re about to kill him, but discover the 22 unit in the back of his van. He assembles it for them, explaining that if his program works, it can be taught. He puts it together and the 22 has the personality of a scared child. Yolandi takes on an immediate mother-role and tells him that he’s a happy chappie…and names him Chappie. They let Deon leave, but he asks to come back to check on the progress. He also tells them that because of the fused battery, Chappie only has about 5 days to live.
Moore wants to work on his Moose, but discovers that the Guard Key is missing. He knows Deon took it.
The next day Yolandi and Amerika start teaching Chappie. Ninja gets mad that because he needs Chappie trained to help them to do one more heist so they can pay back Hippo.
At work, Moore pulls his gun on Deon, but plays it off as a joke. He’s seriously got a screw loose.
Deon leaves work to check on Chappie. He’s mad that the gang is turning him into a thug, so he asks Chappie to promise not to do anything illegal. Moore follows Deon and sees what’s going on. Ninja returns and threatens to kill Deon again for interfering with his plans. He and Amerika take Chappie to the middle of a rough area and leave him there. The locals start attacking him, but because Chappie promised Deon he wouldn’t do anything bad, he doesn’t fight back.
Chappie makes his way back to the gang hideout where Amerika and Yolandi fix him back up. Ninja and Amerika figure out a way to trick Chappie into helping them. Together, they steal cars so they can get money to get weapons so they can do their big heist. Once they have enough cars, they go to a crazy looking apartment building, not completely unlike the building in Dredd. When they get there, a dog fight is taking place. Chappie can’t go up to see the arms dealer Pitbull (Johnny Selema) and get weapons, and a stack of Playstation 4s. When they return, Chappie is trying to nurse a dead dog back to health. Ninja explains to him that in life you can either end up the dead dog, or the winning dog which. He also tells him that his battery can’t be fixed because Deon made him to die. But if he helps them with their heist, they’ll be able to buy him a new body. Chappie goes along with the idea because he doesn’t want to die.
Deon returns to the gang hideout and is disappointed that Chappie is out doing illegal stuff with Ninja and Amerika. Yolandi tells him that he should leave because Ninja will kill him if he finds him there. Chappie, Ninja and Amerika return. Deon tries to reason with Chappie, but Chappie tells him that he’s angry that Deon didn’t tell him that he was going to die.
News stories break that Chappie is out in the world committing crimes, so Moore hunts him down. He manages to capture Chappie and steal the Guard Key from his head. Moore uses the guard key to shut down all of the robocops. Time breaks out all over Johannesburg. Deon finds the Key in Moore’s computer and manages to turn back on Chappie. Before they escape, Chappie sees The Moose. Deon explains that it’s controlled by transferring a human operator’s consciousness via a control helmet. Chappie steals the helmet and they go back to the gang hideout.
At the gang hideout, Chappie rigs up Yolandi’s laptop and all the PS4s to create a super computer. He tests the helmet out on Yolandi and it works!
The gang goes to meet with Hippo, who has changed the deal. He now wants Chappie for himself. Moore sends The Moose in on the deal too. A three way fire fight breaks out. The Moose steps on Amerika and rips him in half. Hippo is killed. Deon gets shot. Ninja creates a diversion so Deon, Yolandi and Chappie can escape. The Moose is about to take out Ninja, but Yolandi surprises it by launching a rocket at it. It turns and shoots Yolandi dead. Chappie jumps back into the action and blows up The Moose.
Chappie rushes Deon back to the lab. Moore is still there. Chappie beats him into a mangled mess, but doesn’t kill him. Deon is seconds away from death, but Chappie puts his consciousness in the one test robot that’s available. Deon, now a robot figures out a way to save Chappie too. He sends Chappie’s consciousness into the nearest fallen Robocop. That works too.
So Deon and Chappie are robots now. Chappie has Yolandi’s consciousness saved on a thumb drive from earlier when he was testing out the helmet. He hacks into the robot factory and has it create a new schematic. Yolandi’s consciousness is transferred into a brand new Fembot.
And they all lived happily ever after…as robots.