Accompanying naturalist Professor Evans into the Everglades in 1860 to study and record wild life in the swamps brought sixteen year old Toby Morgan, son of ailing physician, Dr. Morgan, closer to maturity in many ways. The admiration of Sue, the naturalist's daughter, made the dangers of the swamp seem trivial to Toby. Dr. Morgan averts a smallpox epidemic in the Caloosa Indian tribe, who repay his kindness with hidden treasure. Toby finds his greatest reward in the skeletal remains of prehistoric mammoths and certainty that the naturalist's life is the one he should follow. Buried treasure at the finale is trite, but local color is convincing and the story line is taut.