An extra-terrestrial race called the Boov invades Earth under the command of Captain Smek with a view to claiming the third rock from the sun as their new home. The Boov round up the humans and relocates the entire species. A resourceful teenage girl called Tip, whose mother was abducted, evades capture and goes on the run. She crosses paths with an outcast Boov named Oh, who has been banished by his otherworldly kin. They join forces to save Earth.