Cavendish Square trilogy

Pooling their meager resources, Lady Cornelia Dagenham and her sister-in-law Aurelia spend a month at their friend's house in London, where they meet Lord Harry Bonham, an aristocrat who is out to purchase their friend's property.

Aurelia Farnham believes she is happy living in London's 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 colonel's spy. Now Greville needs Aurelia to continue the patriotic mission and partner...