The Garden Murder Case runs on "passion, avarice, ambition and horse-racing" and the affair leaves the starting gate as DA John Markham is dining with Philo Vance and narrator Van Dine. A strangely cryptic 'phone message is received, leading the latter two to drop in on Floyd, son of chemistry Professor Ephraim Garden. On this occasion, there are several other visitors, there to follow their custom of a bet or two on horse races, placing them by means of a telephone hookup to a news-service giving odds and last minute scratches, wagers being placed with a bookie via another phone line.
Those having a flutter include the professor's wife Martha, Floyd's friends Cecil Kroon, bright young sportswoman Zalia Graem, and would-be thespian Madge Weatherby, not to mention Mrs Garden's medical attendant, Nurse Bernice Beeton. There's also Floyd's cousin Woode Swift, who has lost a great deal of money betting. Despite attempts to persuade him otherwise, he insists on wagering $10,000 on one horse and goes up to the roof garden to listen to the race on a head phone. The horse loses and the ruined Woode commits suicide with the professor's revolver. When this becomes known, more people than might be expected are seized with the desire to visit the roof garden despite explicit instructions they are to stay downstairs until the police arrive to take charge, and it's not long before accusations are flying about like all get out.
Of course it is not suicide but murder. But who was responsible, what was the motive, and how did they pull it off? Then another death occurs. Vance investigates and ultimately gathers the suspects in the professor's den to point the finger. But there is a startling and somewhat unlikely event before all is revealed.
My verdict: The Garden Murder Case involves an apparently impossible crime. How could any of the visitors have killed Swift without being missed from the gathering downstairs, even in the middle of all the gambling excitement? In this entry in the Vance series the culprit is more easily spotted than in other Van Dine novels, but against that handicap readers should bear in mind although the details are intricate they are clewed in fair fashion.