Soon after Queen Isabel of Spain gives birth to her youngest child, an infanta she names Eulalia, the tiny princess is delivered into the arms of her nodriza, Amalia Aragón. A poor woman from northern Spain, Amalia spends nearly two years living in the palace, nursing the royal baby alongside her own infant son, Tomás. Decades later, Tomás is stunned when the princess Eulalia walks into his small bookshop, seeking his help with an audacious project that could shake Spain to its core. Tomás agrees, and the unlikely pair embark upon a life-changing journey across the ocean from Spain to revolutionary Cuba to Gilded Age New York and finally to the dazzling World's Columbian Exhibition in Chicago. Based loosely on the life of the real Princess Eulalia, this clear-eyed and engaging historical novel deftly explores timeless themes of love, loss, family, friendship, and duty, as Eulalia, Tomás, and Amalia navigate the treacherous line between old world and new.