In the late 1880's, some parts of Texas are still overrun by rustlers, despite the efforts of the Texas Rangers. When Ranger Major McNeil enlists Buck Duane, with whom he has worked before, to investigate a ring of rustlers in Exeter County, Buck travels to Exeter with his pal Euchre, an unsuccessful insurance salesman. On the way there, Buck and Euchre see a stagecoach being robbed. One of the passengers, Barbara Longstreth, drives the coach away after the thieves steal her necklace, and Buck and Euchre chase off the two robbers. They then escort Barbara, who has been away studying for four years, to the ranch of her uncle, Judge John Longstreth, who is the town banker. Also at the ranch is Phil Lawson, Barbara's former sweetheart. Unknown to Barbara, Lawson and the reluctant Longstreth are the secret leaders of the gang of rustlers run by Red Morgan. Morgan was also in charge of the attack on Barbara's stagecoach. With Morgan's aid, Lawson and Longstreth have bankrupted a large number of the local ranchers so that their land is subsequently taken over by Longstreth's bank. Now that Barbara has returned, Longstreth wishes to quit the gang, but Lawson tells him he must stay until after an upcoming hijacking of a gold shipment from a nearby mining company. Buck states that he wishes to buy some land in Exeter, and Lawson tells him to contact rancher Clem Mitchell, which Buck does later that night in a hotel saloon. Buck also spots Morgan, his former nemesis, and notices that Morgan has given Barbara's necklace to his girl friend Trixie. Buck takes Morgan and his partner, Fletcher, to the sheriff, but after the sheriff releases them, Buck realizes that he is corrupt and takes them to Longstreth. Lawson also releases the pair and sends them after Buck and Euchre, who have gone to Clem's ranch. Morgan and Fletcher reach the ranch first, and after killing Clem, engage in a shootout with Buck, during which Fletcher is shot. Realizing now that the judge and Lawson are the gang leaders, Buck sends Euchre to get help from McNeil while he returns to the Longstreth ranch. Buck overhears Lawson and Morgan discuss the gold shipment they intend to rob the next day, then captures Morgan, who is shot accidentally by Lawson. Lawson escapes with the rest of the gang, but the judge promises Buck that he will turn himself in to McNeil when he arrives. Buck then leaves for Humboldt, where the robbery is to take place, and waits at the mining company's shipping office. Buck and Lawson shoot each other when the gang arrives, but Buck is only wounded, and the rangers round up the rest of the criminals. Soon after, Longstreth returns all the money and land he took, and Buck and Barbara plan to marry.