Hugh Denvers was sent to Belgrade as a spy towards the end of the Great War, partly under the auspices of Arthur Sinclair who was then working for the British Secret Service. Denvers was to meet an informant, and the two would identify each other by the small silver leopard figures they carried.But Denvers disappeared and he was considered lost. Denvers’ pregnant wife married a war profiteer Jack Marsac, and the child Betty was their daughter. Twenty-one years later Marsac is killed in an automobile accident on the eve of his becoming a member of Parliament. But Sir Arthur Sinclair, now investigating in his famous solo capacity, suspects foul play—especially when a silver leopard is sighted again.'The Silver Leopard', first published in 1941, was the penultimate Masterman mystery; it subsequently became a rarity due to destruction of copies during the Blitz.