Kyle is a young American who lives in Argentina. One morning Hugh, a childhood friend who had disappeared eleven years earlier, knocks on his door. Hugh asks him to let him stay at his house for a few days, arguing that a group of people are looking for him. Soon enough, Kyle will regret agreeing to his friend's request.

A portion of the tail of a prehistoric reptile is discovered in Denmark. It regenerates into the entire reptile, which proceeds to destroy buildings and property and generally make a nuisance of itself. It can fly, swim, and walk, and has impenetrable scales, which makes it difficult to kill.