The original and the archetypal haunted house comedy-thriller. It establishes nearly all of the genre conventions. It's not exactly horror because there is ultimately no supernatural element, but it uses typical motifs from the fright film, particularly its wonderful expressionist look and the spooky sets full of shadows and cobwebs and secret passages.
The much imitated set up is very cute. A family meets in an old castle to hear the reading of a will. The fortune goes to the lead, Laura La Plante, but only if she is considered sane by the psychiatrist who will arrive in the morning. Otherwise it will go to... and then a hairy hand comes out of the wall to snatch away the family lawyer. But whoever it is, they have until dawn to drive the heir clear out of her mind!
Then there are some hidden diamonds and a killer who has escaped from a psychiatric hospital. La Plante looks a little matronly for a horror star now, but thankfully she gives a restrained performance while being scared witless. Creigthon Hall plays the frightened fop who saves her, without being irritating. And there is a long list of the usual suspects.
It works as an exciting thriller, but the comedy (and farce) is effective too and doesn't slow down the action. This is still an enjoyable film which never drags and is told with visual flamboyance by German director Paul Leni making his American debut. When Creigthon Hall is hiding under a bed watching a jazz babe get undressed it's possible to wonder if the horror film has moved on at all!