Jack McColl is an international automobile salesman, travelling the world in search of markets for the luxury Maia he has in train. He is also a spy, moonlighting for the embryonic British intelligence services in the run-up to the First World War. 'Jack of Spies' takes McColl and his sweetheart, the beautiful American socialist Caitlin Hanley, from the brothels and opium dens of pre-war Shanghai to the wet backstreets of Dublin via San Francisco Bay, as they work to foil a German plot that threatens to expose the British Empire's very weakest point.