Like the best of the paperback originals that specialize in crime we get the usual ingredients for a quick read. Fistfights and action galore. Lots of James Hadley Chase style ersatz American dialog meaning it's littered with wiseacre period slang that no real person ever used. A myriad of suspicious characters make trouble for the two cops.
Among those characters are:
Homer Finch -- a salesman on his way to a cosmetic convention. He spends much of his telling stupid jokes and playing pranks with novelty gag items.
Thomas Carpenter -- older gent way too interested in the police business and a bit too interested in other passengers like...
Gloria Starr -- burlesque stripper, con woman who gets Carpenter to pay for her meal in the dining car when she "forgets" her purse
Carol Wallace -- claims to be Maxwell's girlfriend. Attempts to bribe Long with sexual favors in order to free Maxwell.
Long sends orders to headquarters to run criminal background checks on all these passengers and a few more. He suspects that one or more may be involved in a plot to either free Maxwell and get him off the train or to kill him before the train arrives in Phoenix. It turns out he's right, but just who is involved is rather hard to figure out. And there are indeed a few surprises before this action tale comes to its violent finale with plenty of fists and bullets flying.