When Deputy US Marshal Frank Dalton is killed in the line of duty, his brothers Bob and Grat are appointed to replace him. However, when they discover corruption in the higher echelons of the Marshals Service, they resign in disgust. Grat is cheated by a crooked gambler and takes back his money at gunpoint, but that winds up getting them labeled as robbers. Grat is wrongly accused of train robbery and imprisoned. When he breaks out of prison he and his brother decide to take their revenge by actually robbing the express company that falsely accused him in the first place.

Young lawyer Tod Jackson arrives in pioneer Kansas to visit his prosperous rancher friends the Daltons, just as the latter are in danger of losing their land to a crooked development company. When Tod tries to help them, a faked murder charge turns the Daltons into outlaws, but more victims than villains in this fictionalized version. Will Tod stay loyal to his friends despite falling in love with Bob Dalton's former fiancée Julie?