Elizabeth Bonner and her oldest daughter, Hannah, encounter an escaped slave near their village of Paradise, New York, in the spring of 1802. She calls herself Selah Voyager, and she is looking for Curiosity Freeman--a former slave herself, and one of the village's wisest women. The Bonners take the desperately ill Selah to Lake in the Clouds to care for her, and with that simple act they are drawn into the secret life that Curiosity and Galileo Freeman have been leading for almost ten years. While Elizabeth and her husband, Nathaniel, undertake a treacherous wilderness journey to bring Selah to safety in the north, Hannah embarks for New York City to learn the secrets of vaccination against smallpox, a disease that threatens Paradise--and to learn more about Liam, a boy she once loved who has returned as a bounty hunter.