Not long after the invasion and occupation of Earth by a race of powerful robots wanting human knowledge and ingenuity, humans are confined to their homes. Leaving without permission would be to risk their lives. Monitored by the electronic implants in their necks, the robot sentries are able to track the movements of humans in order to control them. And if any person comes out of their home, they are given warnings by the robot sentries to get inside their home. If they do not comply, they are shot immediately.
In what starts out as a bit of fun, a bunch of clever kids in a British town (assumed to be Scotland, but actually filmed in Northern Ireland and Isle of Man) manage to tamper with the implants in their necks and stay out after their curfew. Having discovered the capabilities of the electronic implants, they quickly realise how important this information could be to save the imprisoned human race.
Led by the talented Sean (Callan McAuliffe), who discovers he has the mental ability to interface with and control the robots, the kids band together and recruit other people who want to stand up against the robots’ rule. Standing in their way are human collaborators, led by Smythe (Ben Kingsley, using a northern English accent), and the kids must summon all their emotional and physical strength in order to battle against their control. After a run-in with the collaborators, clues eventually lead them to a hideaway community in an abandoned mine where Sean is reunited with his father, but the robots soon descend on the community seeking Sean, offering an amnesty in exchange for him. Sean mentally controls a robot craft that rams and destroys the cube, the local robot mothership, halting this invasion. He narrowly escapes the impact. He interfaces with a damaged Mediator, a robot in human form, and mentally sends commands to end the invasion of the Earth, destroying the robots and their craft. The film ends with jubilation as the local population celebrate in town. In the closing scene, Sean looks up and sees something looking down from the local castle.