As the freedom of the Jazz Age transforms New York City, the iridescent Mrs. Theresa Marshall of Fifth Avenue and Southampton, Long Island, has done the unthinkable: she's fallen in love with her young paramour, Captain Octavian Rofrano, a handsome aviator and hero of the Great War. An intense and deeply honorable man, Octavian is devoted to the beautiful socialite of a certain age and wants to marry her. While times are changing and she does adore the Boy, divorce for a woman of Theresa's wealth and social standing is out of the question, and there is no need; she has an understanding with Sylvo, her generous and well-respected philanderer husband. But their relationship subtly shifts when her bachelor brother, Ox, decides to tie the knot with the sweet younger daughter of a newly wealthy inventor. Engaging a longstanding family tradition, Theresa enlists the Boy to act as her brother's cavalier, presenting the family's diamond rose ring to Ox's intended, Miss Sophie Fortescue--and to check into the background of the little-known Fortescue family. When Octavian meets Sophie, he falls under the spell of the pretty ingenue, even as he uncovers a shocking family secret. As the love triangle of Theresa, Octavian, and Sophie progresses, it transforms into a saga of divided loyalties, dangerous revelations, and surprising twists that will lead to a shocking transgression ... and eventually force Theresa to make a bittersweet choice.