Barbara Frietchie's eighteenth birthday is interrupted when she sees Union soldiers, who have taken control of her home town, Frederick, Maryland, foraging for food. Her screams bring Captain Trumbull, who arrests his men and, against her wishes, assists her. When Barbara's grandmother, who likes the Yankees, asks her to show Trumbull the flag given to her long ago by Thomas Jefferson, Barbara replies that she tore it because she hates Yankees. After Trumbull helps Barbara's brother Arthur elude capture on his return home, Barbara's attitude softens. When Barbara's father orders the courting captain away, the couple go to a neighboring town to marry, but the Confederates take the town, and Trumbull leaves. Arthur mistakenly shoots him and carries him into their home. Although Barbara prevents the Confederates from entering, she finds Trumbull dead in the morning. Enraged, her grandmother waves the flag, which Barbara mended, at the Union troops. Although Stonewall Jackson orders his men to march on, Jack Negly, Barbara's rejected suitor, fires and fatally wounds Barbara. Her grandmother covers both bodies with the flag.