Rex, a wild stallion, and Rinty, a police dog, are pals. Their master , John Sheldon, is framed for murder, and Alice Ingram plans to race Rex for money to pay for John's legal defense. Meantime, Frank Nolan, who has falsely accused John, sets out to steal Rex for himself.

The exploits of Champion, a wild stallion who befriends twelve year-old Ricky North in the American Southwest in the 1880's. Although Ricky, who lived on his Uncle Sandy's ranch, had a magnetic attraction for trouble, he was always rescued by the Wonder Horse, aided by the boy's other bosom companion, German shepherd dog, Rebel.

In 1865, Captain Mark Smith of the Confederate Army leads a band of deserters to conquer Texas and rule it as a dictator. In one of his first actions, he captures and assumes the identity of Texas' new Finance Commissioner, Colonel Marcus Jeffries, after having the real man murdered. When a contingent of Texas Rangers enters the territory, Snead, one of Smith's men, leads them into an ambush by Smith's "troopers". The Rangers are apparently wiped out, although one injured survivor is left. The survivor, nursed back to health by Tonto, swears to avenge the massacre and defeat "Colonel Jeffries" and his men.

A prospector is murdered by The Cactus Kid and his gang, who hope to find the murdered man's goldmine. The miner's dog, Rin-Tin-Tin, recognizes the killers, who thereafter seek to use the dog to locate the lost mine. With the help of a government agent and a young girl, Rinty saves the mine and brings the bad guys to justice.

Cowboys and a businessman compete to find lost treasure.  

A mysterious master criminal known as The Voice plots with his gang to sabotage the Milesburg Oil Company, but the rightful heir has a secret army of her own to protect her rights.