Foreign correspondent George Gerney, travelling to Moscow by train to report for his newspaper on post-war changes there, finds himself in the company of a pro-Soviet delegation from England. His aloof attitude towards his fellow passengers receives a jolt, however, when one of them is murdered in Moscow. He refuses to accept the official Russian explanation of the crime and, better versed than most foreigners in Soviet tactics of every kind, he does his own investigating – giving a shrewd and often amusing picture of life behind the Iron Curtain.