- Philo Vance, the dilettante detective
- John F. X. Markham, District Attorney
- Ernest Heath, sergent, Homicide squad
- Ephraim Garden, professor of chemistry
- Martha Garden, his wife
- Floyd Garden, their son
- Zalia Graem, friend of Floyd
- Cecil Kroon, friend of Floyd
- Woode Swift, nephew of Ephraim & Martha, a too-heavy better
- Lowe Hammle
- Madge Weatherby
- Bernice Beeton, nurse
Locale: New York City
Synopsis: The Gardens live in a penthouse of a NYC skyscraper. They also own the garden area on the rooftop. They periodically have a party with their horse racing enthusiast friends, and place bets by phone while listening to the races on the radio.
Philo Vance gets a phone call tipping him off that the upcoming party bears watching. He is a slight acquaintance of the Gardens and attends the party. Woode Swift has a habit of placing large bets, then going to the rooftop garden during the race to listen to the results in solitude. Swift plunges and places $10,000 on the horse Equanimity - who loses. Moments after news of the race results are on the radio, a shot is heard from the roof. Swift is found dead. Vance takes a quick look at the body and declares it murder.
It turns out there were two successive shots: the killer shot, and a red herring shot, but which is which? The close timing of the two is critical.
During the investigation phase, nurse Bernice Beeton is discovered trapped in the "vault", a secure storage room, with a broken bottle of bromine gas intended to do her in. Vance finds her in time.
Next matriarch Martha Garden is found to have died overnight in bed, with her prescription bottle empty beside her.
Vance sets up a trap to catch the killer.
The book provides some interesting insights into the horse racing world, and the description of the gathering, placing bets and listening to results on the radio is an interesting insight into the world of the 1930's. The book follows the usual Van Dine formula of the wealthy family whose members do not trust each other. When the matriarch, Martha, announces to the family that she is some annoyed and is going to change her will the next day, you just know she won't make it though the night. (Moral: If you are going to cut someone out of your will, do it before you tell them).
The killer is unmasked in a typical Van Dine trick - nothing the police would condone these days, but back in the 1930's Van Dine's police just sat back and watched the fun; knowing in the end that Vance's vigilante justice would mean no need for a prosecution.
I was peeved that Lowe Hammle, introduced as "fifty or thereabouts" is listed as "elderly" in the list of characters!
For a thorough synopsis and review, I invite you to see Bev Hankin's review on her blog, MY READER'S BLOCK.