The complicated plot has Massey broadcasting arias over German radio to U-Boat captains. Brent is an American agent who knows she's sending out a code. Rathbone is a Scotland Yard inspector (not unlike his regular Sherlock Holmes character) who is also trying to crack the case. It's easy
to get lost in the plot by not paying attention, but there are some nice comic bits along the way. The camera treats Massey in a flattering manner for her first straight role. Don't miss the pre-LONE RANGER appearance by Moore.