Secret Beyond the Door is a 1948 film, directed by the estimable Fritz Lang. It's based on a book published a couple of years earlier called Museum Piece No. 13, written by Rufus King, an American detective novelist. I haven't read the book, but King was an interesting author and I hope to say more about him on this blog in due course. As for the film,it's entertaining and well worth a watch.
The plot seems, on the surface, to follow a familiar pattern. A pretty young woman who has inherited money but is in search of love goes off on holiday to Mexico and falls in love with a man who notices her interest in a knife fight. There's a hint at this stage that her psychology is rather twisted, but I don't think it's a spoiler to say that this angle of the story is not really followed up. She marries the chap after a whirlwind romance,and then her troubles really begin.
In many respects, this is a classic "woman in jeopardy" film, but there are elements in the story which strengthen its appeal. The casting is very good - Joan Bennett and Michael Redgrave (who was very good in creepy parts) are the seemingly ill-matched couple, while Anne Revere, as the husband's sister, and Barbara O'Neill, as his secretary, also contribute to the mysterious goings-on. The big question is - what lies behind a door that Redgrave keeps locked? I guessed the answer, but there is another pleasing plot twist at a later point, and the outcome of the story is not what you might expect.
Lang was a gifted director, and here he makes excellent use of the plot material, even though some of the effects - dramatic storms, and so on - are rather conventional, others are quite striking. The film's producer was Walter Wanger, who was one of Bennett's husbands. They seem to have been an odd couple in their own right. Three years after this film was made, Wanger shot Bennett's agent, whom he suspected of having an affair with her. The scandal, she reckoned, ruined her career, although they remained married for more than a decade. She married again and lived to the age of 80. She's best known for her appearance in certain other movies in the film noir vein, but this one doesn't deserve to be overlooked.