Robert McBee, a tall, handsome young man with dark brown or black hair and grey eyes, grows up in Agatha, Virginia. There, he forms a childhood bond with Jeanie Reed, pledging marriage before his family relocates to Pennsylvania. He promises to return and marry her once settled.

The American Civil War erupts, placing them on opposing sides. Robert becomes a commanding officer and skilled soldier in the Union Army, holding abolitionist views. Jeanie's family resides in Confederate territory, her father James Reed initially holding strong Confederate sympathies and vehemently opposing Northerners. Their romance becomes forbidden, requiring secrecy due to societal and familial consequences.

Robert's presence and beliefs challenge Jeanie's upbringing and ingrained prejudices, acting as a catalyst for her evolving perspective on slavery and racism. Despite the pervasive danger of war, Robert remains committed to Jeanie. During a critical incident where Confederate soldiers surround the Reed household, Robert is present. Facing this confrontation, James Reed experiences a change of heart, grants his blessing to the couple, and facilitates their escape through a secret passage before dying by suicide.

Following the Union victory at the war's end, Robert's fate remains uncertain. The narrative concludes with Jeanie waiting at a tree marked "R+J," leaving his return unresolved.