The Dalton brothers Em, Grat and Bob, destined to blaze a path of violence and infamy across the west's wildest days, begin their life of crime as lawmen. Judge Isaac Parker makes the boys deputies after their law-abiding brother Frank is killed in the line of duty. The troublesome deputies break more laws than they enforce. Soon, their reputation of robbing gambling houses and trains spreads throughout the land. In California, the Daltons acquire an arch enemy, railway detective Will Smith. He puts up a 25,000 dollar reward for their capture - dead or alive.