I'm trying to imagine watching this movie when it debuted in 1939. England is mere months from going to war with Nazi Germany, and director Michael Powell presents a movie featuring submarines and espionage during World War I - told from the perspective of a German infiltrator! Even now, sixty-five years later, it seems like a nervy choice - what would it have been like then and there, especially considering how sympathetic the spy is portrayed as being.And Captain Hardt (Conrad Veidt) isn't a monster - when we first meet him, the U-Boat captain is just returning home for a little shore leave after a couple months at sea, only to be greeted with tight rationing and an immediate assignment to set sail through an English minefield to the isle of Foy, up in the Orkney Islands, to meet with a British traitor and use his information to sink the fleet. His contact is Frau Tiel (Valerie Hobson), who has taken the place of the island's new schoolteacher, a Miss Anne Burnett (June Duprez). Hardt comes off as a world-weary but principled patriot, showing disdain for the traitor whom he must deal with (Sebastian Shaw) and keeping his German Navy uniform - if he's to die, it will be as a sailor, not a spy.
Taking the German point of view adds an extra thrill to many of the proceedings - though Hardt seems all right, if stuck by happenstance of birth on the wrong side, others are less admirable. The introduction of Anne feels like the introduction of any thirties ingenue - and is quickly followed by her being kidnapped and thrown off a cliff. It's delightfully sinister, and keeps the audience's attention until the plot starts twisting.
I'll try and avoid how the plot twists - although most descriptions I've seen tend to include stuff that you really aren't told until the second half of the movie - but lets just say the Germans' operation develops a few hitches, but they also prove fairly resourceful, leading to an aquatic sequence that has both naval and espionage components. The effects for that are pretty well-done, too - I never got the feeling that I was looking at miniatures, or that I was seeing stock footage (as in The Caine Mutiny). It's not quite up to modern standards, but it's not bad, either.It's a clever little movie, filled with genuine tension that builds up to a reasonably satisfying denouement. And if it plays that way on late-night American public television in 2004, it must have been a real corker in 1939 Britain.