A brilliant young biologist Dr Seth Forest travels to South America with his wife and son, determined to solve the greatest mystery of the natural world, the secret of communicating with animals. He cracks the code, but triumph is short-lived when his wife is kidnapped by the evil Professor Scabelax. Ever since, the Doctor and his son Adam (now fluent in many animal languages) have sailed the world searching for her. Then they receive news that a woman matching Adam's mother's description left a letter with authorities in a city on the other side of the world. Unknown to Adam and the Doctor, Scabelax has lured them to the city to complete his terrible plan for world domination. As the different elements of the plot converge, a spectacular finale awaits . . .