Late one night, Guido Brunetti is called away from dinner to investigate the death of a widow in her modest apartment. Though there are some signs of a struggle, the medical examiner rules that she died of a heart attack. It seems there is nothing for Brunetti to investigate.

But he can’t shake the feeling that something or someone may have triggered her heart attack, that perhaps the woman was threatened. Conversations with the woman’s son, her upstairs neighbor, and the nun in charge of the old age home where she volunteered do little to satisfy Brunetti’s nagging curiosity. And with the help of Inspector Vianello and the ever-resourceful Signorina Elettra, he intends to get to the truth.