In the winter of 1820, the New England whaling ship Essex was assaulted by something no one could believe: a whale of mammoth size and will, and an almost human sense of vengeance. The real-life maritime disaster would inspire Herman Melville's Moby-Dick. But that told only half the story. This story reveals the encounter's harrowing aftermath, as the ship's surviving crew is pushed to their limits and forced to do the unthinkable to stay alive.

In 1846, waves of Irish immigrants poured into the New York neighborhood of Five Points. "Billy the Butcher" bands his fellow "Native Americans" into a gang to take on the Irish gang "The Dead Rabbits," organized by Priest Vallon. After an bloody clash Vallon is dead and his son ends up in a brutal reform school. In 1862, that boy returns to seek vengeance against the man that killed his father.