The Henry Brothers are opposites: Rob, dark and intense, is shy and a perfectionist, while redheaded Jamie is an easygoing, sociable fellow. They have quarreled and competed with each other since they were small boys. It is therefore not surprising that when Rob becomes a Confederate reenactor, Jamie shows up as a Union drummer boy. Also at the reenactment of the Battle of Antietam is the object of their latest competition: the lovely Sarah Singleton.

Dressed in Civil War-era clothes, the three pose for an old style photograph, only to mysteriously travel back in time to the actual Antietam campaign in September, 1862. This is the story of their separate but intertwined adventures:

• Rob, as a Rebel soldier, endures a long and deadly march to battle only to end up facing his own brother as the enemy
• Jamie, as an aide and courier for Union General George McClellan, incurs the wrath and suspicions of the Yankee spymaster, Allan Pinkerton
• Sarah, as a volunteer nurse’s aide, joins forces with Clara Barton as they desperately try to save lives on the bloody battlefield

This time the brothers really are at war!