Wanderers of the West (1941)

Tom Mallory, posing as a wanted man known as Arizona,is searching the west for the cattle rustler who killed his father, and his only clue is the name Westy Mack. He and his pal Slim meet a ranch foreman, Waco Dean, who is a cattle rustler on the side and is also the hunted Westy Mack. Waco tells Tom he can lead him to Mack if he will help Jake Benson and his men rustle the herd from the ranch Waco works for. Tom learns that the ranch is owned by an old friend of his, Laura Lee, and her ten-year-old sister Sugar.