The twelve-year old heir to a fortune decides to fight back after he learns that his avaricious uncle is out to kill him in this thriller. He learns of the plot after his uncle, who is next in line for the fortune, generously invites him to visit him on a remote tropical island. To help foil the man's evil scheme, the boy enlists the aide of a young girl. It's a good thing too as the wicked relative has written a book on how to kill people and uses every trick in it to kill him including sharks, poison mushrooms, tarantulas, fire, and hypnotism to do the deed. When the children begin trying to beat him at his own game, a deadly game of cat and mouse ensues until the uncle finally calls it quits and leaves the islands.