This is the third in the Starbuck chronicle series, set in the American Civil War. Nat Starbuck is a Northerner, the son of a preacher, who has come to the South and enlists as a soldier in the Southern army. He finds he has a talent for soldiering and participates in some of the bloodiest battles of the war. And bloody they certainly are; the descriptions of the slaughter are vivid and bring its horrors dramatically before the reader's eyes. In this installment we find Starbuck taking part in General Robert Lee's invasion of the North, which culminated in one of the fiercest engagements of the war, the battle of Antietam. Starbuck has to contend not only with the enemy but also with some of those on his own side who would like him dead.
Starbuck's story is, as usual, the main focus of interest but we also follow the fates of some other characters in the saga, particularly Starbuck's friend Adam Faulkener, who meets his death.
Cornwell's novels about Sharpe, the British soldier in the Napoleonic wars, are probably better known than those about Starbuck, having been made into a television series; but I find the American setting to be more vividly realized in some ways, probably because all the characters speak English so the books mostly avoid being marred by Cornwell's rather cavalier attitude to linguistic matters.