Dull, workaday life at the Navy weather station base on Gow Island is broken up -- violently -- when a transport plane from the antarctic, on a routine approach for re-fueling, sudden reports trouble and crash-lands. Most of the scientists and crew who were supposed to be aboard are missing, and the one man they do find, the pilot, is in a shock and can't speak. Then the local bird population gets disturbed, and soon people are disappearing, all while the scientists try to figure out the connection between all of these events and a corrosive residue that starts turning up. It later becomes clear that the island, now cut off from the outside world, is under assault by some kind of carnivorous species than can resist most weapons and breeds very fast. Lt. Charles Brown (Anthony Eisley), in temporary command, has to hold together his small navy crew and a coterie of scientists (Walter Sande et al) and civilians, including a nurse (Mamie Van Doren) in whom he has more than a professional interest.