In a high-tech military laboratory, a group of scientists has developed a series of sophisticated robots designed for warfare, known as the Strategic Artificially Intelligent Nuclear Transport, or S.A.I.N.T. units. During a demonstration of these units' capabilities, a freak lightning strike hits one of the robots, Number 5, instigating a malfunction that imbues it with sentience and self-awareness. Confused and curious about its new-found consciousness, Number 5 inadvertently escapes from the facility, driven by a desire to learn more about the world around it and to understand the concept of life.

Once outside, Number 5 encounters Stephanie Speck, a kind-hearted animal care provider who, mistaking it for an alien, takes it into her home. As Stephanie realizes Number 5's true origins, she becomes fascinated by its innocence and eagerness to learn. They form an unlikely friendship, with Stephanie teaching Number 5 about human culture, life, and morality. Meanwhile, the military, led by Number 5's creator, Dr. Newton Crosby, and his assistant, Ben Jabituya, launches a desperate search to recover the robot, seeing it as a malfunctioning piece of expensive equipment rather than a sentient being. This sets up a clash of values between the military's desire to control or destroy what they don't understand and the compassion of individuals who see value and potential life in the machine.