Undercover Man

Mexican rancher Tomas Gonzales and his ranch hands cross the border into Texas to consult with Captain John Hawkins about American raids on Mexican ranches. Hawkins, an old friend of Tomas, tells him in turn that Texans have been raided by Mexican outlaws. Realizing that they would be recognized if they tried to investigate themselves, Hawkins sends for his friend, Hopalong Cassidy. On their way, Hoppy and his friends, California Carlson and Breezy Travers, are ambushed, but manage to scare off their attackers in a gunfight. Tomas warmly welcomes Hoppy and his friends to his ranch, and introduces them to his right-hand man Miguel, his daughter Dolores, and his American friend, Donna Louise, and her son Bob, who have lived with him since the death of Donna Louise's husband years earlier. California immediately becomes friendly with the widowed cook, Rosita, while Bob and Breezy vie for the affection of Dolores. When the wagon train from a local mine is attacked, Hoppy and local ranchers ride to the scene of the crime, but the bandits have escaped with the gold by the time they arrive. The next day, Hoppy, California, Breezy and Miguel are out riding when another mule train is attacked, and rancher Chavez privately tells Tomas that he saw Hoppy with the outlaws. Tomas doubts that Hoppy could be an outlaw, but warns Miguel not to leave the American's side. Meanwhile, a freight wagon is attacked in Texas, and witnesses report having seen Tomas at the scene of the crime. When Hoppy visits Hawkins, he meets his deputy, Ed Carson, and Hawkins warns Hoppy to be wary of Tomas, although he doubts his old friend is a thief. California's romance with Rosita progresses, but he is unaware that Miguel has withheld a letter informing her that her husband is alive and will be returning soon. One night, Hoppy and his friends spread out and watch the departures from the hacienda. Breezy follows a man riding a white horse, who he thinks is Hoppy, but to his surprise, the rider fires at him and he is forced to turn back. Tomas rides up as Breezy tells Hoppy what he saw, and both Hoppy and Tomas confide their suspicions about each other. They then realize that someone they know must be working against them, and follow the rider's tracks to the abandoned Gonzales winery. Inside, California finds a secret doorway in a wine casket, which leads to a cave where horses and clothing matching those worn by Hoppy and Tomas are kept. Hoppy is suspicious of Bob, who only recently returned from college and may have known about the cave since childhood, and the next day, he and his friends follow Bob from the hacienda to a remote shack. There Bob confers with Carson, the cover leader of the outlaws, who refuses to accept Bob's resignation from the gang. Hoppy rides to the local sheriff and finds an old wanted poster with Carson's picture on it. When another freight wagon is attacked, Hoppy and a posse of ranchers open fire against the outlaws. Hawkins arrives with his deputies soon after and arrests the gang. When a rider resembling Hoppy attempts to escape, Hawkins fires his gun, and is shocked to discover that the rider is Donna Louise. Donna Louise confesses that the ringleader was blackmailing Bob, who was wrongly accused of murder. Donna Louise submitted to the blackmailer's demands that she impersonate Hoppy and Tomas to mislead the investigators. Bob then admits to having advised the outlaws of mine shipments. Donna Louise passes out before she can name the ringleader, but Hoppy has already singled him out as Carson, and informs Hawkins that his deputy is actually a wanted outlaw. Carson is arrested and the hacienda returns to its normal activities. California is shocked when Rosita's husband comes to reclaim his wife, and has to be restrained against harming Miguel by an amused Hoppy.