Harry Birsch is thought to be a loyalist living in the American colonies, but when George Washington offers him money in exchange for sensitive information about the British, Harry scoffs at the idea. He exchanges the information not for the monetary gains, but what he can do for America. And so he begins a journey in which he spies for the Americans in an attempt to win the war. In doing so, he must masquerade as a traitor. The real truth is the secret that can never be revealed lest the reputation of all he holds dear will fall.

James Fenimore Cooper is best known for his "leather stocking" novels concerning American Indian life and the frontier. His most famous novel is Last of the Mohicans. The Spy is the first novel with espionage as the main theme and is the novel that garnered him much fame.