Hannay is commissioned to give a fortune in uncut diamonds to his guardian's old adversary, Desmond Leigh.
Three months later in England, Hannay finds Desmond Leigh. He is married to a beautiful young woman called Barbara, but is a drunken wastrel with many enemies.
When Leigh is subsequently murdered, Hannay finds the perpetrator of the crime and hands him over to the police.
Leigh's wife is greedy, and is after the diamonds for herself. Greed, disloyalty, marital infidelity and violence ultimately lead the characters in this dramatic episode of Hannay to their predetermined ends.