Red oozes from the patient's gums. He has a rushing headache and the whites of his eyes look like lemons. He will likely die within days.

Here is the true story of how four Americans and one Cuban tracked down a killer, one of the word's most vicious plagues: yellow fever. Set in fever-stricken Cuba, the reader feels the heavy air, smell the stench of disease, hear the whine of mosquitoes biting human volunteers during the surreal experiments. Exploring themes of courage, cooperation, and the ethics of human experimentation, this gripping account is ultimately a story of the triumph of science.