The Dragon’s Teeth (#14)

After the death of his longtime friend Inspector Rummell, Ellery Queen drops in on Rummell’s son, a struggling lawyer named Beau. Before their meal is through, Queen and young Rummell are partners in a newly minted company: Ellery Queen, Confidential Investigations. Rummell promises not to burden Queen with any of the work—he only wants to capitalize on the name of the world-famous amateur sleuth. But when they are hired by an eccentric millionaire who refuses to say just why he wants their services, Rummell has no choice but to turn to Queen for help. And when their client dies at sea, they discover that the wealthy old man had countless enemies who might have put him out of his misery—most of them within his own family.