It is late 1864 and the Civil War is still raging even though the South teeters on the brink of defeat. Carter Willoughby, a circuit-riding minister looking for lodging appears at the home of Susannah Lander, a poverty-stricken Quaker woman who lives in South Central Pennsylvania with her maiden aunt. Carter's mission as a Confederate spy is to study and plan the destruction of the Horseshoe Curve, an engineering marvel that makes it possible for trains to scale the Allegheny escarpment. Putting the curve out of service would send notice that the Rebels can strike anywhere to disable the Union's vaunted transportation system. The people of the Great Cove, a prosperous farming community look upon Carter with suspicion, but Susannah rents to him anyway. She needs the money. Susannah hates slavery, despises the South and doesn't mind a good argument, so her sharp tongue and analytical mind combine to discourage any but a prickly relationship. So begins a connection no one would take for love, and yet... Carter, struggling with doubts about the Confederate cause, continues to put duty before doubt, pursues his goal and keeps up his disguise. Despite enduring suspicion and uncertainty, the unlikely couple slowly develop a strong attachment. Local suspicion and an unexplained death add to the tension, but finding a way to love your enemy takes them past the war and into a promising but uncertain future.