"The Copperhead" is a narrative centered around the tensions and conflicts during the Civil War era, particularly focusing on the character of Abner Beech, a farmer labeled a "Copperhead" for his Southern sympathies in a predominantly abolitionist community. This label exposes him to hostility from his neighbors, who even resort to violence when they attempt to tar and feather him. However, after a grave incident where Abner's home is set ablaze, the community reflects on their actions, seeks his forgiveness, and strives to mend their relationships, illustrating the complexities of human emotions and societal divisions.

Key characters in the story include Jee Hagadorn, Abner's abolitionist neighbor and adversary, and Jeff Beech, Abner's son, who serves as a Union soldier and harbors feelings for Esther Hagadorn, Jee's daughter. The narrative also introduces various supporting characters, such as the orphan Jimmy, Abner's wife M’rye, and others that contribute to the rich tapestry of life in Dearborn County. Through the interplay of these relationships and conflicts, "The Copperhead" explores themes of community, forgiveness, and the personal costs of political beliefs, providing a nuanced perspective on this tumultuous period in American history.