Twenty years ago, Dexter Stardust barely got out alive when the Vreesians—inhabitants of the menacing Planet X—sent a fleet of robots to wipe out all life on Earth. He has been living with that close call ever since. Now a mechanical man from the 10th planet arrives with a message that changes everything: Dexter is the key to saving both humans and Vreesians. Alongside his good friend Aurora, the taco-loving Dexter sets out on the greatest adventure of his life to discover the mystery of the Robot from Planet X.