This is the third of Trollope's Pallister novels and one of his most compelling works. The plot centres on the fabulous necklace owned by the Eustace family, which the beautiful but ruthless opportunist Lizzie, claims as her own after she marries Sir Florian Eustace for his money and becomes his widow after only a few months. Lizzie plots to keep the necklace, while at the same time she spreads her net over several prospective new suitors, in order to entrap another husband to keep her in the manner to which she has so rapidly become accustomed.

This novel is both a gripping detective story and a fascinating study of moral duplicity.