Overland Telegraph

After wandering cowboys Tim Holt and Chito Rafferty help Terry Muldoon, who works for her father's Arizona telegraph operation, down from a telegraph pole, she suggests that they seek jobs with Col. Marvin at nearby Fort Craig. Unknown to Terry, Marvin has just been ordered to close down his outpost because the telegraph has rendered the fort obsolete. When Marvin breaks the news to Paul Manning, who has been supplying the fort with equipment and horses, Paul accuses Muldoon of withholding information that would have prevented him from going into heavy debt. Although Marvin tells Paul that Muldoon was not aware of the Army's plans, Paul confers with his best friend, Brad Roberts, a wealthy Mesa City saloon owner, about the situation. Brad assures Paul that the matter will be resolved and that Paul and his sweetheart, singer Stella, should proceed with their wedding plans.

Later, the still unemployed Tim and Chito are heading back to Terry's camp when they hear an explosion. Tim and Chito ride up just as three masked men are destroying the camp and telegraph wires. Tim shoots and wounds one saboteur, Steve, before all three flee on horseback. Assuming that Steve will need a doctor, Tim and Chito ride to nearby Mesa City. There, Steve and his cohort, Bellew, find the doctor absent and go to Brad's saloon office for help. When Tim and Chito walk into the saloon, having seen Steve and Bellew's horses outside the doctor's office, Brad shoots off his gun, then claims that a drunken Steve shot himself. Bellew, meanwhile, sneaks off and hides the horses. Although suspicious of Brad, Tim and Chito have no hard evidence against him and return to Terry's camp. There, Terry accuses Paul of ordering the sabotage, but he maintains his innocence. Terry then hires Tim and Chito as guards and assigns them to meet the next day's stage from Crockerville, on which her father is traveling with a $10,000 payroll. At the same time, Paul pays off Bellew in Brad's office, happy that the sabotage has earned him $50,000 in delays. After Paul leaves, Brad, who was once Stella's beau and is still in love with her, hires Bellew to steal Muldoon's payroll, knowing that Paul will be suspected.

The next day, Bellew and fellow masked henchman Joe hold up the stage and are surprised to find Stella on board. The men grab Muldoon's bag and Stella's purse, then shoot Muldoon. Tim and Chito arrive in time to chase the men off and rush Stella and Muldoon to town. There, Chito escorts Paul to jail to await the sheriff, while Tim and Stella take Muldoon to the doctor. Muldoon soon dies, however, and when Terry learns the news, she storms off to form a lynching party for Paul. To prevent a hanging, Tim and Chito race to the jail, and there Paul admits he was behind the sabotage but refuses to implicate Brad. Tim convinces Paul to ride to Crockerville, where he and Stella are to be married in a few days. Bellew eavesdrops on their plans and reports to Brad, who orders Paul be killed.

Lying in wait on the trail to Crockerville, Bellew and Joe open fire on Paul, wounding him. Bellew escapes but Tim captures Joe. While Chito guards Joe, the unsuspecting Paul guides Tim to Brad's nearby ranch home to recuperate. Bellew, meanwhile, reports to Brad at the saloon, and worried that Joe will talk, Brad orders Bellew to round up some men to find him. At Brad's house, Tim happens to find Stella's stolen purse, and Paul finally reveals Brad's part in the sabotage. Paul also deduces that Brad is trying to frame him because of Stella. Out on the trail, Chito identifies Joe's horse as one he saw outside the doctor's office and, leaving Joe tied up, races to inform Tim. Unguarded, Joe is freed by Brad, Bellew and his men, who then head for Brad's house. Sent back by Tim, Chito spies the men charging off and rushes to Terry's camp for help. At Brad's house, Tim and Paul engage in a shootout with Brad's gang. Brad orders Bellew to set his house on fire, but Tim and Paul put out the flames. Then, just as Chito arrives with Terry, Tim dashes out to shoot and capture Brad. After Bellew and his cohorts are rounded up, Tim exonerates Paul. Later, Tim, Chito and Terry see the newly married Paul and Stella off on their honeymoon.