During a vacation together on a cruise ship, Tatopoulos and Audrey Timmonds find themselves under attack (by coincidence, of course) by a gigantic, sea going mutant turtle. The two manage to escape from the ship unscathed, and seek safety on a nearby tropical island. Once there, they discover a gigantic mutant lizard that resembles a colossal komodo dragon [in real life, komodo dragons are a dangerous, land roving species of monitor lizard, which routinely reach lengths of ten feet or more, normally feed upon pigs and other large animals, and are indigenous to the Galopagos Island chain, which was the spot of Charles Darwin's early and revolutionary studies of evolution in the 19th century).