Scotland, 1912. Antonia McCulloch’s life hasn’t gone the way she planned. She and her husband, Malcolm, have drifted apart; her burgeoning art career came to nothing; and when she looks in the mirror, she sees disappointment. But at least she will always have Balmarra, her family’s grand Scottish estate, and its exquisite glass house, filled with exotic plants that can take her far away. When her estranged brother’s wife, Cicely Pick, arrives unannounced, with her young daughter and enough trunks to last the summer, Antonia is instantly suspicious. What besides an inheritance dispute could have brought her glamorous sister-in-law all the way from India?

In February 1887, Caitriona Wallace and Émile Nouguier meet in a hot air balloon, floating high above Paris, France --- a moment of pure possibility. But back on firm ground, their vastly different social strata become clear. Cait is a widow who, because of her precarious financial situation, is forced to chaperone two wealthy Scottish charges. Émile is expected to take on the bourgeois stability of his family's business and choose a suitable wife. As the Eiffel Tower rises, a marvel of steel and air and light, the subject of extreme controversy and a symbol of the future, Cait and Émile must decide what their love is worth.