This piece of tacky WW2 propaganda has Bela Lugosi kill off various fith columnists and leave their corpses outside the Japanese embassy in Washington (with a prominently placed "Closed" sign on its door). Most of the film has Bela darting in and out of various "hidden" rooms in his main foe's rather small house and sneaking up on people from behind them. For example, everyone enters the cellar by going round the side of the house and through some front doors above the cellar; Bela, however, appears to get in via some inside door (so he doesn't have to leave the house). In a scene near the end he drags one of his victims through a previously unseen curtain in the living room and into some huge, medieval-type room with a long table that had previously not featured in the house at all and had somehow been missed by the large contingent of FBI men. Another scene has him sneak into a small room below the stairs, as hero and heroine ascent the stairs, so he can somehow get into the upstairs room of his Doctor victim before the others. These momentary pleasures, though, are outweighed by the ludicrous climatic flashback plot revelation in which it is revealed that Lugosi is a Nazi plastic surgeon who has transformed Japanese agents into these American-looking fifth columnists. The daftest moment, in a thoroughly daft film, comes when Lugosi is double-crossed by the fiendish Orientals and thrown into a cell into which, conveniently, is another prisoner who looks exactly like him (but sans beard) and is about to be released. The Great Man gives a chuckle and takes out his beard-trimming kit (that the Japanese have helpfully left him with). Welcome to Monogram; a Universe all of its own. See also The Ape Man and The Corpse Vanished for more of the same.
Review of Black Dragons
