It's 1871. 12-year-old Billy McCarty and his immigrant Irish family have to leave New York and travel west to seek new opportunities. But the journey proves fatal for some.

Kathleen and her sons Billy and Joe travel on to Santa Fe. Life is hard, but she meets and marries a man who might change everything for the better - only to find that he makes it a lot worse.

Antrim, Kathleen and the two boys relocate to Silver City, trying to start a new life. But all their dreams are shattered - and Billy loses everything.

Billy finds fresh trouble when he falls in with a character called Alias. He kills a man in self-defence and ends up on the run, and then in the arms of a young woman who also happens to be the girlfriend of Jesse Evans.

Billy, on the move again, ends up in Chihuahua, New Mexico, with a new Mexican friend called Segura; together they enjoy several risky escapades -- but in the end, Billy risks losing his life.

Billy joins Jesse, Pat Garrett and another outlaw called Frank Baker, as well as the rest of the 7 Rivers Gang in their new camp just outside the town of Lincoln. The gang is now working for Lincoln's most powerful boss, Major Murphy.

We are on the eve of the Lincoln County War. Jesse and the gang are encouraged by Murphy to ramp up their attacks on those famers, mostly Mexican, who have signed up with Tunstall.