I Spy is a historical novel set during the World War I while English and French allied forces were on their knees as the Germans progressed on the western front. In the meantime, some seriously perilous spy games are being played by all interested sides. The situation calls for a Detective Mitchell of the Washington, DC police who gets to grips with the world of secret services, spies and agents.

Natalie Sumner Lincoln (1881-1935) was an American novelist who wrote mystery and crime novels mostly set in her native Washington, DC. Lincoln wrote 22 novels half of which featured either Inspector Mitchell or Detective Ferguson of the Washington, DC police.