In order to extract a confession from the murderer, amateur sleuth Colonel Gethryn fabricates a story of how the murder was committed involving doppelgängers, a bastard brother, and a body switcharoo. If only that had been true. It was so much more interesting than what happened.
None of the characters, including Colonel Gethryn, were likable or even interesting. Gethryn unappealingly falls madly in love with one of the murder suspects right off the bat and they each spend the novel swooning, although it takes her much longer to figure out why she's doing so.
Our attention is repeatedly drawn to how white the women are, especially Lucia, Gethryn's paramour. Her hands, her face, her skin, her throat, are so white. Gethryn's friend Spencer Hastings is falling in love with his secretary, and thinks of her as "that little white darling."
Lucia, who is 30, is called "middle-aged." (This was common in fiction of the time - 1924).
The anti-Semitism is undisguised: "I always knew she kept a pretty Jewish fist on the purse-ropes, though," says someone about a gentile. A private eye is referred to as "a little, dapper, sly-eyed Jew" who lisps and reveals how greedy Jews are by demanding an extra two hundred pounds after he's already been paid fifty.
I learned a few new words: "fan-tods" are a very bad mood or a feeling of extreme upset or anxiety. A "tonneau" is a barrel-shaped open rear passenger compartment of a car. A "doss-house" is a cheap rooming house (flophouse).