Pretty much a classic Edagar Wallace thingie. The plot is convoluted, the characters come and go. We have some kind of criminal who shows up at restaurants with a white mask covering his face. He robs people and disappears. We have a medical doctor who takes care of poor people. We have a lovely young woman who has a bit of money who helps the doctor. She has a suitor, of sorts, who is a journalist. Then, there are some people who seem to have had some shady interactions back in South Africa and Australia.
Sadly, I didn't write about this when the story was fresh in my mind, so I can't provide much by way of details. It hardly matters. Edgar Wallace was once wildly popular, and I don't see why that still isn't the case. He plots very interesting, and garish, story lines.