Jack McColl is a globe-trotting salesman for a luxury car firm. He is also a part-time spy for the fledgling Secret Service on the eve of the First World War. As 1913 ends he is in China, checking out the German naval base at Tsingtao between automobile demonstrations in Peking and Shanghai. Caitlin Hanley is a young Irish-American journalist with the sort of views that most British men would find dangerously advanced. McColl is no exception, but once captivated he finds himself unwilling to give her up even when Caitlin's radical politics and family connections threaten to compromise his secret career. Then the pair become involved in a plot that threatens the Empire in its hour of greatest need.