After a lightning bolt zaps a robot named Number 5, the lovable machine starts to think he's human and escapes the lab. Hot on his trail is his designer, Newton, who hopes to get to Number 5 before the military does. In the meantime, a spunky animal lover mistakes the robot for an alien and takes him in, teaching her new guest about life on Earth.

Robot Johnny 5 moves to the city to help his friend Ben Jahrvi with his toy manufacturing enterprise, only to be manipulated by criminals who want to use him for their own nefarious purposes.