Nathaniel King left New York City in 1828 to venture into the vast unexplored regions beyond Mississippi. He heads west, lured on by dreams of wealth based on his uncle's promise to share with him "the greatest treasure in the world".

Matt Bardoul was a good man to have as a friend and a bad one to make trouble with. He was also a single-minded drifter—until he met his match in an outspoken beauty named Jacquine Coyle. She was headed into the Bighorn Mountains with her father and an expedition in search of gold. After Matt signs on to join them, he discovers that there is a group of outlaws in the party—gunfighters and thieves that Matt wouldn’t trust for a minute.

Joe Pickett is the new game warden in Twelve Sleep, Wyoming, a town where nearly everyone hunts and the game warden—especially one like Joe who won't take bribes or look the other way—is far from popular. When he finds a local hunting outfitter dead, splayed out on the woodpile behind his state-owned home, he takes it personally. There had to be a reason that the outfitter, with whom he's had run-ins before, chose his backyard, his woodpile to die in.

On nothing more than a lark, he leaves his family and begins a journey from Ohio westward. Along the way, he runs up against badlands and bad men, loses his freedom, gains his freedom and learns the first rule of the frontier: Do whatever it takes to survive. With ruthless enemies after him - both White men and Indians - he’ll head for a place as brutal as it is beautiful - the wilderness of the Rocky Mountains.

It began with gold that had once belonged to Montezuma. Stolen and cached in a church in Mexico, it was recovered by two army officers who fled north for the French settlements. Along the way one stabbed the other to death. The remaining officer was eventually killed by Plains Indians, but he buried the treasure just before he died. Now Ronan Chantry, a handful of trappers, and an Irish girl whose father was killed after telling her a few vague landmarks are searching for the lost treasure. But they are not alone.