During the bloodiest single-day battle in American history, Anson Baird, a surgeon for the Union Army, is on the front line tending to the wounded. As the number of casualties rises, a mysterious soldier named John comes to Anson's aid. Deeply affected by the man's selfless actions, Anson soon realizes that John is no ordinary soldier, and that he harbours a dangerous secret. In the bizarre aftermath of the Battle of Antietam, this secret forges an intense bond between the two men. Twenty years later on the Fraser River in British Columbia, Anson arrives to find his old comrade-in-arms mysteriously absent, an apparent victim of the questionable business ethics of the pioneer salmon canners. Haunted by the violence of his past, and disillusioned with his present, Anson is compelled to discover the fate of his missing friend, a fate inextricably linked to his own.