When the Calico is about to be struck by a falling satellite, Godzilla is called to the rescue. Although the Big G saves the crew by catching the satellite, energy emissions from the device create a freak time warp that sends Godzilla and the Calico back one million years in the past. There they are soon attacked by a Diplodocus, who the much larger Godzilla easily drives away with a few spurts of his fiery breath [actually, the Diplodocus, a prehistoric herbivore which resembled the Apatatosaurus in body form but was lighter and much longer in length with a somewhat elongated head, was a peaceful creature and shouldn't have attacked the crew; for that matter, dinosaurs of that type became extinct before the end of the Jurassic Period, over 100 million years ago, and shouldn't have co-existed with either the Tyrannosaurus or the cavemen seen later in this episode].

While exploring the prehistoric terrain, the crew meet and befriend a tribe of cavemen who they teach to defend themsel