The Secret of Poo Mountain: Book 4 (Library Binding) (ISBN-13: 9798765627648)

Dr. Egg, Dr. Yang, and Dr. Woong face their biggest challenge yet. They must climb the tallest mountaintops and search the deepest forests for the fabled Golden Poo. Along the way, they'll learn about animals living in these mysterious habitats through the spectacular science of poo. But Poo Boy is up to his old tricks, so the three heroes will need to put all the poop-y clues together to solve this mystery once and for all.