The America of the 1860s - a young nation at war within itself. As young men rushed forward to fight, many to die and many more to be wounded and maimed, a farming community in Western Pennsylvania offered up its sons to form a light artillery battery in the Pennsylvania Reserves. Among them were three brothers, one of whom on arrival in Washington purchased a diary to record his experiences in the first vital year of a war that defined a nation. 150 years later, that diary forms the basis of this story of the war in the Eastern Zone, of the commanders, the battles, the wins and losses. Most of all, it tells the tale of what became known and has since been commemorated as Cooper's Battery B. And of the ""great Slaughter"" that engulfed them and those around them.