Slick gambler James Wylie is apprehended by the law and given the option to forgo a prison sentence if he poses as a bandit. His mission is to uncover the identity of the Poet, a notorious outlaw who has been holding up bank-owned stagecoaches and leaving verses at the crime scenes to taunt the authorities. James finds time to woo the Poet's lovely wife, Ann, who initially cold-shoulders him. But, as a romance develops, they partner up to find the robber.

Mission to Moscow was made at the behest of F.D.R. in order to garner more support for the Soviet Union during WWII. It was from the book by Joseph E. Davies, former U.S. Ambassador To Russia. The movie covers the political machinations in Moscow just before the start of the war and presents Stalin's Russia in a very favorable light. So much so, that the movie was cited years later by the House Un-American Activities Commission and was largely responsible for the screenwriter, Howard Koch being Blacklisted.