Dr. Marina Singh, a research scientist with a Minnesota-based pharmaceutical company, is sent to Brazil to track down her former mentor, Dr. Annick Swenson, who seems to have all but disappeared in the Amazon while working on what is destined to be an extremely valuable new drug. Nothing about the assignment is easy: not only does no one know where Dr. Swenson is, but the last person who was sent to find her, Marina's research partner Anders Eckman, died before he could complete his mission. Plagued by trepidation, Marina embarks on an odyssey into the insect-infested jungle in hopes of finding Dr. Swenson as well as answers to troubling questions about her friends death, the state of her company's future, and her own past.
Once found, Dr. Swenson, now in her seventies, is a ruthless and uncompromising as she ever was back in the days of Grand Rounds at Johns Hopkins. With a combination of science and subterfuge, she dominates her research team and the natives she is studying with the force of an imperial ruler. But while she is as threatening as anything the jungle has to offer, the greatest sacrifices to be made are the ones Dr. Swenson asks of herself, and will ultimately ask of Marina.