The plot focuses on McGee's investigation of a beautiful young woman who is mysteriously losing her mind without any apparent physical or mental disease.

Poking around where he's not wanted - as usual - McGee delves into the mystery of a rich and beautiful wanton who happens to be losing her mind, a little piece at a time.

As he probes, he uncovers some of the strange corruptions that simmer behind the respectable facade of a quiet Florida town..." Several years before the events of the novel, McGee had brief romance with a widow who was grieving the death of her husband.

At the time of the novel's publication, a package being delivered in a plain brown wrapper was also understood as implying erotic, illegal or potentially embarrassing material.

[1] The McGee novels all had colors in their titles, a mnemonic device Macdonald invented to help readers recall which books in the series they had read.