June 1864: the Civil War is now into its fourth year of bloody conflict with no end in sight. The armies of the North are stalled in fetid trenches outside of Richmond and Atlanta, and the reelection of Abraham Lincoln to a second term seems doomed to defeat—a defeat that will set off the call for an end to the conflict, dismembering the Union and continuing slavery.

Only one group of volunteers for the Union cause is still eager for battle. Nearly two hundred thousand men of color have swarmed the recruiting stations and are being mobilized into regiments known as the USCTs, the United States Colored Troops. General Ambrose Burnside, a hard luck commander out of favor with his superiors, is one of the few generals eager to bring a division of these new troops into his ranks. He has an ingenious plan to break Fort Pegram, the closest point on the Confederate line, defending Petersburg—the last defense of Richmond—by tunneling forward from the Union position beneath the fort to explode its defenses. Burnside needs the USCTs for one desperate rush that just might bring victory.

The risks are high. Will Burnside be allowed to proceed or will interference from on high doom his plan to failure? The battleground drama unfolds through the eyes of James Reilly—famed artist, correspondent, and friend of Lincoln, who has been employed by the president to be his eyes and ears amongst the men, sending back an honest account of the front. In so doing, he befriends Sergeant Major Garland White of the 28th USCT regiment, an escaped slave and minister preparing his comrades for a frontal assault that will either win the war, or result in their annihilation.