When a letter arrives from Swenson, reporting Dr. Eckman's death, both his widow and Mr. Fox want Marina to go to Manaus to find out what happened and ascertain the status of Swenson's research. Marina does not want to go, but she succumbs to the pressure and heads out on her journey. She spends several weeks in Manaus--sans luggage--trying to make contact with the young couple who are the gatekeepers to Dr. Swenson and wandering through the city, reflecting on her earlier life. While Marina's back story is interesting, she still somehow fails to come completely alive as a character, and the section of the book set in Manaus drags.
Dr. Swenson finally makes her appearance, however, and Swenson agrees to take Marina to her research station. From here, the pace of the story picks up, with a number of intriguing developments. Marina learns new and startling information about Swenson's research, is forced into providing medical services to the Lakashi (and into reexamining why one bad outcome caused her to leave the practice of medicine), and tries to find out exactly what happened to Anders. The ending is both startling and somewhat unsatisfying, as I still felt unsure about what path Marina will follow when she returns to Minnesota.
At that moment, she understood why people say You might want to sit down. There was inside of her a very modest physical collapse, not a faint but a sort of folding, as if she were an extension ruler and her ankles and knees and hips were all being brought together at closer angles.
Marina filled her lungs with frozen air and smelled both winter and spring, dirt and leftover snow with the smallest undercurrent of something green. . . . Instead of growing up inquisitive and restless, she had developed a profound desire to stay, as if her center of gravity was so low it connected her directly to this particular patch of earth.