One of the several adaptation of the Edgar Wallace play is a typical, but unfortunately quite imperfect old dark house mystery about the last members of the once wealthy and prestigious Lebanon family. The family's head is Lady Lebanon, who rules the house with an iron fist and her sinister looking servants follow all her orders, that include keeping and eye on everyone, especially her only son, who is the last bearer of the name. She wants him to marry Isla Crane, her secretary, who also happens to be his cousin, but that seems to be no problem for Lady Lebanon, on the contrary actually, as we learn that it's been an on-going habit to marry family members.. which somewhat foreshadows the later turn of events.
A young lad called Richard Ferraby arrives to the house to discuss renovation plans and him and Isla, who is not too keen on the marriage idea anyways are immediately attracted to each other. Soon, the family's chauffeur gets killed, strangled with a scarf and Lady Lebanon's plan start to fall apart even further. It becomes obvious that she has many things to hide, including a locked room upstairs, some secrets with the family's doctor called Amersham and also, a scarf, that she tries to burn when police starts to investigate. While Lady Lebanon does everything to stop the investigation or at least make it as difficult as possible, both Ferraby and Lord Lebanon (who is clearly more interested in composing music than in the future of the family) try to help the rather incompetent police officers, but they can not prevent another murder from happening.
The film has everything that could make it a good old dark house mystery: family secrets, an old mansion, locked rooms, sinister butlers, secret passages and more-or-less likeable heroes, but it just does not work out at the end. The story has potential but it is heavily handled, dialogues are often awkwardly badly written, the acting isn't much better for the most part and director George King does not do a very good job either. He is well-known for his horror movies starring Tod Slaughter, so he should know a thing or two about scares and how to create a threatening atmosphere, but still, this movie completely lacks suspense.
And a friendly warning: if you watch this on Odeon Entertainment's Best of British DVD (that was actually the first time the film was made available for the public since its initial theatrical run), do not look at the photos on the cover unless you don't mind spoilers, as they give away both the movie's final plot twist and ending.