After establishing Fred MacMurray and Joan Crawford as newlywed Americans in England, planning honeymoon in south of Germany just prior to outbreak of the war, yarn has British secret service drafting them for mission to secure vital confidential plans for the secret weapon – a magnetic mine. Pair pick up the trail in Paris and then hop to Salzburg, where it becomes a mysterious chase with various and sundry characters peering out of shadows and suddenly turning up in the most approved spy fashion.
Picture is filled with various incidents that crop up and then vanish, with no reason for their inclusion except to confuse the audience and by-pass straight-line exposition of the tale.
Both MacMurray and Crawford competently handle their roles, despite drawbacks of script material. Conrad Veidt clicks solidly in major supporting spot, along with brief appearances of Basil Rathbone as a Gestapo leader.