The House of Secrets starts with an intriguing shipboard encounter: Leslie Fenton (as Barry) assists Muriel Evans (Julie) escape the unwanted attentions of a stranger. She thanks him nicely—but when he attempts to take a look in her handbag for whatever it was the stranger was after, she—get this—throws the whole bag overboard rather than let him see its contents! Hmm, mysterious.
Not surprisingly, they soon meet again (in a major but not shocking coincidence, she happens to be living at the large estate he has just inherited), and she becomes one of numerous characters determinedly resisting Barry's attempts not only to enter his own property, but to find out what the heck is going on. These characters include practically everyone else in the story—his detective friend, Julie's scientist father, some police and government officials, and a gang of crooks after a hidden treasure.
The plot is fast-moving and fairly intricate, and the dialog is mostly sharp. However, as the story progresses, frustration builds—not only for Barry but for us viewers, who also have no idea why everyone is trying so hard to keep him in the dark. By late in the film, my own sympathies had shifted almost entirely over to the gang of crooks, because at least they were straightforward about what they wanted, which is something you can't say about any of the other characters.
The movie also features an ancient document written in "old English," which means it has some words like "ye" and "olde" in it, that is fun for the gangsters to try and sound out. And an inn landlady offers some entertaining colloquial dialog, like her criticism of her husband's aches and pains: "He calls it rheumatism, but I calls it arthritis. I likes to keep up to date." Nothing is particularly authentic, but hey, I point that out in fun, not as a real quibble with the film. Overall, the dialog is one of this film's quite interesting qualities.
Overall: well done—but maddening.