Not to put too fine a point on it, Kaspar Kenting is a rotter. There are hints he has affairs, it is well known he gambles too much, and furthermore he is not very nice to his wife Madelaine. So it is not surprising that when he is kidnapped from his bedroom more than one member of the extended household mutters good riddance.
One of them is Madelaine's neurotic brother Fraim Falloway, who lives upstairs in the Kenting house with their mother, herself quite unwell. Kaspar's broker brother Kenton has charge of the Kenting finances and administers them jointly with Eldridge Fleel, lawyer and family friend. The pair recently refused Kaspar's demand for an outrageous amount of money and this, coupled with certain evidence on the scene, leads to an initial conclusion the kidnapping is bogus and Kaspar is using it as a way to get $50,000 to pay off his debts. However, after a quick stagger about the household Philo Vance begs to differ and as usual he is right. It is not a simple kidnapping case at all.
My verdict: Without, I hope, giving too much away the reader should remember there is no honour among criminals and this novel amply demonstrates it. As usual Van Dine offers a fair bit of misdirection (although one incident is virtually pointed out to be such via Vance's observations on it, a misstep on Van Dine's part IMHO) and DA Markham displays his usual impatient patience with Vance's refusal to even hint at his theories on whodunnit and why. To my surprise there is gun play, demonstrating Vance is not just an airy utterer of arcane knowledge and thus displaying a hitherto overlooked aspect of his character.