The unfortunate thing about war is that neutrals sometimes have to suffer.
By the time director Michael Powell and screenwriter Emeric Pressburger got to work on their second collaboration, 1940's Contraband, World War II had broken out, allowing them to embroil their characters in a more contemporary wartime espionage tale. They stuck with the same stars, though, casting Conrad Veidt in a rare heroic lead as the captain of a Danish freighter carrying much-needed medical supplies for his country who resents being held up by British Contraband Control, with Valerie Hobson as a particularly troublesome passenger who sneaks off his ship, compelling Veidt to follow her and find out what she's up to. Pursuing her to a blacked-out London, he sticks to her like glue despite her best efforts to elude him, and lands in hot water when they're captured by a German spy ring. Only then does he realize how high the stakes are in the game they're playing.
Speaking of which, the film culminates in a terrifically suspenseful game of cat and mouse in a plaster statue warehouse, which prefigures a similar sequence in Stanley Kubrick's Killer's Kiss by a decade and a half. And there is some wonderful comic relief courtesy of Hay Petrie's dual performances as Veidt's first officer and his own brother, a testy restauranteur who comes through in the clutch for Veidt. I do have to wonder, though, what the Danes thought of the insinuation that they're always spoiling for a fight. Then again, this was before Denmark was occupied by the Germans, so maybe that was Powell and Pressburger's way of attemping to nudge the country into taking a side, much as they would try to do with the United States in the following year's 49th Parallel.