The District of Columbia in 1859 isn't the nicest place to live, but Fiona Ellicott loves her job as the director of the Smithsonian Institution Library. The Smithsonian's first paid female employee, she delights in working at "the Castle." She only wishes she weren't losing her assistant—and best friend—Nicole to marriage. Quaker Caleb Fox stays so busy running a Friends' orphanage in Georgetown that he rarely pauses to think about romance. But all that changes when he visits the Smithsonian Library to research a lesson for the children and meets Fiona. Soon, they're organizing a charity concert for the children to perform at the Castle on Christmas Eve... and falling hopelessly in love. But married women are typically barred from the professions, and Fiona faces a choice that will end in heartbreak either way.