Let the unknown = X! A crowded street car! A man is murdered! Everyone saw him die, but no one saw the killer! Many people (even his own partner) had good reason to hate Longstreet. Inspector Thumm's few clues all led up a blind alley. He finally sought the aid of Drury Lane, retired Shakespearean acto, who made a hobby of solving crimes. Seated amid the splendor of the vast medieval halls of his castle on the Hudson, Drury Lane hears the story from the Inspector. He knows who the murderer is, but refuses to reveal his identity until he has sufficient evidence for the police to arrest him. This story is crammed full of chilling thrills! Why was the streetcar conductor murdered? Why won't Longstreet's partner talk? The answers to these questions and others all lead to the solution of this puzzling mystery.
New York City, the early 30's. A man is poisoned on a crowded streetcar during rush hour. Everyone saw him die, but no one saw the killer! And far too many people had good reason to hate Longstreet. The few clues lead up to a blind alley, and District Attorney Bruno and Inspector Thumm pay a call on Drury Lane.
Drury Lane! Retired Shakespearean actor. Matinee idol. Master of disguise. Amateur sleuth who finds "crime the highest refinement of human drama." Ellery Queen's most flamboyant creation.
Seated amid the splendor of the vast medieval halls of his castle on the Hudson, Drury Lane hears the story. Almost at once, he knows who the murderer is, but refuses to reveal his identity until he has sufficient evidence for the police to arrest him.
In the great tradition, all the clues are scrupulously presented to you, the reader. Can you solve the case before the police?

First appearance of Drury Lane himself, his associates, and his gift for disguise.Drury Lane, admittedly greater than life, is well delineated, as well as his supporting cast and his ambience as the best parts of this book concern these characters. It may not be as well known as the Queen books featuring Ellery Queen. Fetching backgrounds (New York circa 1932), a  nasty murder method, and a dandy sleuth: retired Shakespearean actor Drury Lane.His estate on the Hudson shows EQ's interest in design, just like the references to Art Deco in The French Powder Mystery. The plot deals with three murders committed on transport (e.g. trams,  ferries and trains), with the murders themselves being peculiarly nasty (the first murder shows some of EQ's gift for surrealistic mise-en-scčne as it is committed by means of a nicotine-tipped-needle-filled cork ball put into the victim's pocket), including Ellery Queen's first 'dying message' (the second would appear in The Siamese Twin Mystery) - and the ingenious. The finale is deductive, as in all of the early EQ books, but the solution is somewhat far fetched, and the mystery plot is not especially imaginative.It shows similarities to both Conan Doyle's  A Study in Scarlet and one of the stories from G. K. Chesterton's The Innocence of Father Brown".