Years ago, Marina Singh traded the hard decisions and intensity of medical practice for the quieter world of research at a pharmaceutical company, a choice that has haunted her life. Enveloping herself in safety, limiting emotional risk, she shares a quiet intimacy with her widowed older boss, Mr. Fox, and a warm friendship with her colleague Anders Eckman. But Marina's security is shaken when she learns that Anders, sent to the Amazon to check on a field team, is dead-and Mr. Fox wants her to go into the jungle to discover what happened.
Plagued by trepidation, yet propelled by her sense of duty, Marina embarks on an odyssey into the unknown, down into the Amazonian delta, deep into the dense, insect-infested jungle to find answers from the company's research team. Led by the formidable Dr. Annick Swenson, the scientists are looking into the development of a new drug that could have a profound impact on Western society. But the team has been silent for two years and the daunting Dr. Swenson does not like interlopers inserting themselves in her work, as Marina well knows. The eminent and fiercely uncompromising doctor was once her mentor, the woman she admired, emulated, and feared. To fulfill her mission, Marina must confront the ghosts of her past, as well as unfulfilled dreams and expectations-a journey that will force her to make painful moral choices and take her deep into her own heart of darkness.