Frustrated by their inability to take action against a murderous gang who killed a young boy, Texas Rangers Stony Brooke (Robert Livingston), Rusty Joslin (Raymond Hatton) and Rico Rinaldo (Duncan Renaldo) hatch a plan: Stony poses as an outlaw dubbed The Laredo Kid to lure the bad guys into Texas. But the plan might fall apart when the real Laredo Kid arrives on the scene in this action-packed Western.
Roy is an oil prospector. His efforts to get drilling rights on an old Spanish land grant are countered by gamblers from an off-shore gambling boat determined to control the land (and oil) themselves.
Cameo Shelby is running a crooked lottery out of El Paso and treasury agent Bill Elliott has been sent to break it up. When Bill intercepts a shipment of tickets to New Mexico he forces Shelby to send incriminating papers in the next shipment. Bill captures these also and now has the evidence he needs to go after Shelby.
Gary Gray arrives only to be caught up in the rustling activities of Ben Holt and his gang. First Holt brands him for rustling and then frames him for murder. Proven innocent, Gary foils the gang's stage holdup and then heads after Holt whom he now knows to be the real killer. But Holt knows he is coming and waits unseen in ambush. Written by Maurice VanAuken
The blacksmith of a small western town finds himself an outcast. He had led the townspeople west in hopes of starting a new life, only to find the town that they founded is to be bypassed by the railroad.
Assigned to catch a gang of outlaws, officers Bruce Kenton and Paddy Halloran rescue Helen Morgan when her wagon is attacked by the very same gang. Through a ruse, Kenton manages to infiltrate the gang, which is holed up in the lawless community of Caribou Flats. While in the employ of villainous trading post operator Jack Blake, Kenton discovers that Blake is not only the leader of the gang but also the man who murdered Helen's brother.
An evil deputy is using Indian half-breeds to rustle cattle. This causes trouble between the cattlemen and Indians. Hoppy, Windy and Lucky see that justice is served. Songs abound.
Tiger Thompson promises a dying train robber to mind his innocent daughter and return the stolen loot. Along the way, Thompson is attacked by the dead man's gang but manages to reach the law (and the girl) in one piece and with the stolen money intact.
While the original title, "Trailing the Killer" isn't a misnomer, it was a bit misleading since the "trailer" is a dog named Caesar (Caesar the Dog) and the killer is a mountain lion. But the makers also pointed out that Caesar "is the most intelligent dog actor since Rin-Tin-Tin" which probably lured a few Rin-Tin-Tin fans with a show-me attitude. Caesar prowls around the woods of the Northwest, dispatches a rattlesnake, visits his she-wolf mate and their pups, pauses to watch the dainty habits of a raccoon personally washing every morsel of food before eating it---and that raccoon had enough food to use up several minutes of running time---and then saves sheepherder Pierre (Francis McDonald)) from getting eaten by one mean mountain lion. Rin-Tin-Tin he ain't, but then who was?
Returning to his father's cattle ranch after the excitement of serving in combat overseas, Bud McGraw becomes restless, and his father decides to send him to an old friend who commands the Border Police in Texas. On the way he meets Peggy Hughes, accompanying her Uncle Graham, a customs inspector, and he retrieves her hat from the rails of a train. At the headquarters, numerous scrapes and fights win him the admiration of, and friendship with, the men. Lazaro, a Secret Service agent, invites Mrs. Graham and Peggy, who are staying at the border station, for an automobile ride, and they are captured by bandits and held for ransom. Bud and his pals deliver the ransom and discover that Lazaro is the bandit chief. Lazaro refuses to release Peggy, but a jealous rival, Nita de Garma, causes his downfall and shoots him as the Border Police arrive to rescue the party.