The Sword of Antietam is a novel by Joseph A. Altsheler set during the American Civil War. The story follows three young Union lieutenants, Dick Mason, George Warner, and Frank Pennington, as they prepare for the Battle of Antietam. The opening chapter sees the trio surveying the countryside, searching for any sign of Confederate General Stonewall Jackson's forces. The three boys are described as thin but strong and brave, and are all wearing faded blue Union uniforms. As they wait for their sergeant, Daniel Whitley, to join them, they discuss the war, their hopes and fears, and the importance of staying focused on their duty. Eventually, Whitley arrives, and the group makes their way toward the battlefield, where they will face unimaginable danger and hardship. Throughout the novel, Altsheler weaves together a powerful story of courage, sacrifice, and friendship, as his characters fight to protect their country and their beliefs in the face of overwhelming odds.