Not long after Earth is invaded and occupied by a powerful extraterrestrial race of robots seeking human knowledge and ingenuity, humanity finds itself confined to their homes, risking their lives with every step outside. With electronic implants in their necks allowing robot sentries to monitor human movements, stepping out without permission could result in immediate execution, as the sentries issue warnings to return home before counting down the seconds.
In a small rural town in England, a determined teenager named Sean Flynn](/actor/callan-mcauliffe) starts his search for his missing father, Danny (Steven Mackintosh), who disappeared shortly after the invasion. Sean desperately shares hand-drawn missing posters hidden in tennis balls and fruits. Meanwhile, his friend Nathan attempts to fix his PlayStation, only to be accidentally shocked by a young boy named Connor. Observing the situation is a girl named Alexandra, and surprisingly, this electrical shock leads to an unexpected discovery: Nathan's implant has been disabled. Realizing this could give them a chance, the group decides to perform the same procedure on each other, allowing them to venture out without being tracked.
Their adventure leads them to a local museum, and from there, Sean proposes they search for his father at the school where records of the captured are stored. They soon learn that Danny is alive, relocated to a nearby hotel, but their triumph is short-lived as they're soon captured. They find themselves in a room equipped with a deep scanner. Here, the collaborator with the robots, Robin Smythe, interrogates them about how they turned off their implants. Their reluctance to answer results in dire consequences, as Sean's uncle is brought in and transformed with a black implant, followed by a terrifying deep scan that threatens his life by exploring his mental faculties. Despite the agony, hard-headed Sean refuses to give Smythe the information he seeks, ultimately leading to his own deep scan. In a moment of defiance, Sean insults Smythe, inadvertently causing a disruption that allows him to escape. Connor comes to the rescue, bursting in with a makeshift fireworks launcher, saving his friends from the grim fate they faced.
The children seek refuge in a bowling alley, where they once again manage to turn off their implants before sprinting to the hotel. After hiding from a massive robot in a narrow doorway, Sean surprises everyone by suddenly gaining control over the giant machine.
Their journey brings them to a woman named Monique, who is also desperate to discover how to disable her implant. In exchange for this knowledge, the boys meet Swanny, who has successfully had his implant removed by a watchmaker. Swanny sends them on a quest to find a Stone Circle. However, things take a darker turn when an announcement echoes, revealing that Sean's mother, Kate, has been taken hostage at the area headquarters, a looming castle. With Monique's aid, the children manage a daring approach to the castle, only to be threatened by the large robot again. In an unexpected twist, Sean realizes that the black implant gives him an advantage — he can control the robots.
While chaos unfolds, Smythe attempts to manipulate Kate into compliance, but an alarm interrupts their conversation. As chaos reigns, Sean's moment of peril arrives when he seemingly finds himself captured by the robot. However, he cunningly turns the weapon of the large robot on Smythe and his team, disarming them effectively. Meanwhile, Kate’s daring escape on horseback compels Smythe’s team to chase her, which exposes Sean to the devastating firepower of two clankers, insect-like robots armed with laser weaponry. Just as the odds seem insurmountable, Sean seizes control of the large robot and turns its weapons against the clankers, achieving a hard-fought victory.
Reunited with his mother, Sean and his friends venture to the Stone Circle, where they decode a graffiti message leading them to a secret human camp within an old tin mine. But their triumph is short-lived as the robots descend upon the camp searching for Sean. In a tense moment, he chooses to reinstall his black implant and mentally commandeers a robot craft, orchestrating a collision with the local robot mothership, the Cube, dramatically halting the invasion.
In the aftermath, as Smythe tries to flee the chaos, the destruction of the mothership results in his own demise as the robots do not recognize him as an ally. Sean continues to interface with a damaged Mediator, commanding the end of the robotic threat, decisively dismantling the invasion and ensuring humanity's safety.
The film concludes with scenes of jubilant celebration as the town rejoices. However, as Sean gazes up at the night sky, he senses the inevitable return of the robotic menace, a determined expression crossing his face as he resolves to be ready when they come back.
