Aurelia Farnham believes she is happy living in Londons stylish Cavendish Square. But with her friends Livia and Cornelia both married now, Aurelia is the only one still husbandless, and sometimes she longs for more. Then Colonel Sir Greville Falconer storms into her life, delivering a letter from her late husband, a war hero, which reveals he was a spy — the colonels spy. Now Greville needs Aurelia to continue the patriotic mission and partner him as he exposes a ring of Spanish spies who have infiltrated London society. The attentions of the charismatic Greville excite Aurelia as his mock courtship blurs the line between pretense and reality. When the simmering attraction between them ignites into passion and the danger of Aurelias double life escalates, Greville insists on marriage as the best way to protect her. Now Aurelia realizes she has more than shadowy antagonists to fear, for shes lost her heart to a dashing spymaster who will one day slip away as suddenly as he appeared....