It is 1942, and to aid its intelligence gathering efforts, the United States War Office authorizes a surveillance case to capture the meeting of two strangers in a park in Brooklyn. One is a federal agent named Archie Frayn, the other a Japanese ex-patriot hiding out in the United States under the Chinese name Shen Li. Li is one of many Japanese in the United States assuming Chinese or Korean identities to avoid persecution. Agent Frayn’s proposition to Li is simple: Spy on his fellow Japanese ex-patriots, or end up in an internment camp. Li cooperates. And as a reward for his cooperation, he is allowed to exchange letters and photos with his family in Japan—an impossibility during wartime. This exchange of intelligence for family news continues over the next three years, always under the watchful eye of the evolving surveillance technology. Frayn and Li also see their relationship evolving as they watch each other relate to family and struggle with their loyalty to the war effort. A friendship begins to develop between them—a friendship that will eventually change the course of World War II.