In late nineteenth-century London, fourteen-year-old Enola Holmes, much younger sister of detective Sherlock Holmes, turns to Florence Nightingale for help when her investigation into the disappearance of a Crimean War widow grows cold.

From his 1776 Pennsylvania homestead, thirteen-year-old Samuel, who is a highly-skilled woodsman, sets out toward New York City to rescue his parents from the band of British soldiers and Indians who kidnapped them after slaughtering most of their community. Includes historical notes at the end of each chapter.

After fourteen-year-old Enola Holmes seeks the missing Duquessa Del Campo in the seedy underbelly of nineteenth-century London, she finally reaches an understanding with her brothers Sherlock and Mycroft.