Philo Vance receives an anonymous letter warning of deadly danger to the wealthy Llewellyn family heir, Lynn. Eccentric widow Priscilla Llewellyn presides over a society family filled with greed, ego and unhappy marriage. Her secretary Doris becomes romatically involved with Vance, and the two are soon entangled in a mystery of murder and attempted murder involving poison and heavy water experiments.
Philo Vance receives an anonymous letter warning of deadly danger to the wealthy Llewellyn family heir, Lynn. Eccentric widow Priscilla Llewellyn presides over a society family filled with greed, ego and unhappy marriage. Her secretary Doris becomes romatically involved with Vance, and the two are soon entangled in a mystery of murder and attempted murder involving poison and heavy water experiments.