In the near future, crime is patrolled by a mechanized police force. When one police droid, Chappie, is stolen and given new programming, he becomes the first robot with the ability to think and feel for himself.
When Tony Stark and Bruce Banner try to jump-start a dormant peacekeeping program called Ultron, things go horribly wrong and it's up to Earth's mightiest heroes to stop the villainous Ultron from enacting his terrible plan.