The Three Troubledoers.

Set in the old west, the stooges become marshals in a town with a high death rate for lawmen. The boys set out prevent a marriage between the villain Blackie and the heroine Nell, who's father Blackie has kidnapped. The stooges manage to defeat Blackie and his henchmen, but when Nell's father learns she promised to marry Curly if he could save her, he decides death would be a preferable fate.