Dr. Cassandra Reilly is surprised to find herself time-traveling again, this time to New York of 1853, accompanying the internationally acclaimed artist, Evie Johnston. Evie has funded the trip, explaining that she wishes to meet her ancestors, activists in the Underground Railroad. However, the beautiful painter has another agenda altogether. When they arrive in the pre-Civil War city, Evie's deception embroils both her and Cassandra in the activities of the abolitionist revolutionaries, a situation fraught with danger, as well as unexpected romance. Cassandra struggles to keep history intact, and to keep herself and Evie from falling victim to a gang of human traffickers. All the while, each woman discovers how the past has a way of becoming all too personal and present, as they both fall under the spell of the time and the people they meet.