Arnold "Doofus" Duckwaddle, a confused passenger, accidentally opens the cockpit door, landing on a deserted island with hyperintelligent ape Darwin. Darwin, adopted by scientist Will Fly, knows how to deactivate Earth's protective shield. With Fly gone, they face crazed alien Mondu, set on turning Earth into fast-food chain Terra Bytes. Racing against time, Doofus and Darwin must unlock the shield's secrets to save the planet. Will they succeed, or will Mondu's fast-food frenzy prevail? The fate of Earth hangs in the balance.