Mahoney is a movie cowboy fired by his studio. Along with Donnell, a reporter, he accidentally discovers that the latest residents of Arnold's "singing dude ranch" are really bank robbers. It's all pretty hokey, starting off as a parody of B westerns but turning into a parody of itself.
Arnold made a rare screen appearance, which really was just an excuse for him to sing. His agent at the time was "Colonel" Tom Parker, who would later do an entire series of films with his number one discovery, Elvis Presley.