A girl thought to have died years previously turns up at the home of her mother just as her brother is found murdered. Clearly somebody is trying to kill the family off, but is it connected to the girl, and is she really who she says she is?

A series of murders appear to be connected to an old friend of the Chief's, an ageing woman from San Francisco's old rich set; and when the murders are linked to her debutante's ball and she appears to be exhibiting signs of deteriorating mental health, the odds look stacked against her. As always, though, the Chief looks elsewhere to find the truth.