In 1856 Philadelphia, runaway slave Genie Oliver uses her dress shop as a front for her work with the Underground Railroad; and reluctant heiress Abby Read runs a rooming house not just because she hates the life of the idle rich society woman, but because she has no intention of ever marrying a man. When the daughter of Abby's free black servant is grabbed by rogue slave catchers, an unlikely group of people come together, first out of necessity, and then, gradually, in friendship. And in the case of Abby and Genie, something much more.