Dr. Marina Singh is a pharmaceutical researcher with a firm that is seeking a potentially lucrative answer to extending women’s fertility. When a cryptic note arrives from South America, announcing the death of a colleague, Marina is sent to the sweltering Amazon jungle to investigate. Her meeting there with 73-year-old, pregnant, Dr. Annick Swenson, Marina’s former mentor and hero, leads to insights that a sterile lab would never provide. Ms. Patchett captures the chaos of the jungle in her prose, but the heart of the story lies in the conflict between the pharmaceutical company’s desire for profit and the morality of developing a drug that could have profound negative effects.