Three generations of the Leonides family live together in a large, if somewhat crooked-looking house. Then the wealthy patriarch of the household, Aristide, is murdered-injected not with insulin for his diabetes but with a killer substance.

Suspicion falls on the whole houselhold, including Aristede’s two sons, his widow – fifty years his junior – and even his three grandchildren. Could any member of this family have had a hand in his death? Can Charles Hayward, fiance of the late millionare’s granddaughter, help the police find the killer?