The Daltons Ride Again (movie, 1945)

In this action western, the notorious Dalton Boys have decided to go straight and move to Argentina. Just before they leave, they learn of a friend whose land is about to be seized by a greedy land company. Before they can help, the man is killed by a company assassin. The brothers do manage to rescue his widow and head for the hills. There, they decide to revert back to outlaw life. Meanwhile, a newspaper publisher's daughter falls for one of the brothers.