Charley Quinn is twelve years old the summer after his older brother, Johnny, is killed at Gettysburg. Charley can't wait for the opportunity to avenge Johnny's death by killing off some Rebel soldiers. Meanwhile, he works as an errand boy for his older sister, Noreen. He picks up supplies and hats for her sewing business and delivers them when Noreen is finished with them. Charley is a member of the street gang known as the Bowery Boys. Their arch rivals are the Dead Rabbits. As Charley is returning home one day with a hatbox, he encounters a member of the rival gang and gets into a fight. A police officer breaks it up and takes Charley home. Noreen is angry that he has ruined his good clothes and that he had been fighting. While Charley is changing, he hears Noreen talking with her fiancé. At the end of that conversation, Noreen agrees that if Charley can't stay out of trouble she'll send him to a school for incorrigible boys.

Charley is furious and goes out where he encounters a military parade. He recognizes Con Sullivan, a man he believes to have been Johnny's friend. As he pours out his troubles to Con, Charley decides that he wants to run away and join the army. Though he's only twelve, Con encourages the decision and helps him sneak aboard a military transport ship. When they arrive at their destination, Charley is taken on as a drummer boy. He plans to take the first opportunity to avenge Johnny's death. But when the fighting starts, Charley discovers that he's afraid. He sees a man who had befriended him lying dead and picks up the man's weapon, firing on an enemy soldier. The elation he'd expected is replaced by horror that he has taken a man's life and Charley runs away. As he runs, some men call him "Charley Skedaddle." Some try to stop him but he gets away and is taken prisoner by the Confederates. A Confederate officer tells Charley that he doesn't belong in prison and advises that he go west.

Charley escapes to the Blue Ridge Mountains but is hungry. Granny Bent catches him trying to steal eggs from her hen house and takes him in. She's a healer though some think she's a witch. She begins to teach Charley about farming and herbs and he begins to take pride in his abilities. When Granny is called away to assist with a birth, a panther attacks, killing most of the chickens. That night, Charley hears the cat on the roof. The next morning he kills the animal as it springs to attack him. He then has to go find Granny who has fallen and hurt her leg. Charley helps her home and nurses her back to health.

Before it's time for him to leave the mountains in front of the invading Confederate Army, Charley learns that bravery is doing what's necessary even when there's no one around to witness the act. Armed with this new self-confidence, Charley prepares to leave the mountains but vows that he'll someday return.