Amrapali Anna Singh is an historian and analyst capable of discerning the most cryptic and trivial details from audio recordings. One day, a mysterious man appears at her office in Dutch Harbor, Alaska, having traveled a great distance to bring her three Type IV audio cassettes that bear the stamp of a library in Buenos Aires that may or may not exist.

On the cassettes is the deposition of an adventure journalist and his obsessive pursuit of an amorphous, legendary, and puzzling "City of Dreams." Spanning decades, his quest leads him from a snake-hunter in the Louisiana bayou to the...