US cavalry officer James Laurence (Nelson Eddy) arrives at one of the Russian colonies to pave the way for the eventual American takeover of the territory. He faces resistance in the form of Prince Nikolai Balinin (Hugo Haas), who has no intention of weakening his despotic hold over the local peasants. The plot thickens when Laurence falls in love with Natalie Alanova (Ilona Massey), the wife of disgraced nobleman Count Igor Savin (Joseph Schildkraut).