An alien is left behind on Earth and saved by the 10-year-old Elliot who decides to keep him hidden in his home. While a task force hunts for the extra-terrestrial, Elliot, his brother, and his little sister Gertie form an emotional bond with their new friend, and try to help him find his way home.

David, a robotic boy—the first of his kind programmed to love—is adopted as a test case by a Cybertronics employee and his wife. Though he gradually becomes their child, a series of unexpected circumstances make this life impossible for David.