This is the third of Buchan's Richard Hannay novels, following The Thirty-nine Steps and Greenmantle. Set, like Greenmantle, durinig World War I, it deals Brigadier-General Hannay's recall from the Western Front, to engage in espionage, and forced (much to his chagrin) to pose as a pacifist. He becomes a South African conscientious objector, using the name Cornelius Brand. Under the orders of his spymaster, Sir Walter Bullivant, he travels in the book through England to Scotland, back to the Western Front, and ultimately, for the book's denouement, into the Alps. Those who know Greenmantle will meet some old friends again here, including Bullivant, the American John Blenkiron, the South African Peter Pienaar and others.