Desperadoes' Outpost

During the Spanish American War, federal investigator Allan "Rocky" Lane is assigned to stop an outlaw gang around El Morado that is ambushing stagecoach drivers and wrecking the coaches, causing delays in mail service. Rocky meets first with the owner of the stagecoach line, Nugget Clark, who has seen all of his coaches destroyed by the gang, except one, which he cannot afford to repair. After deciding to work undercover as Nugget's new driver, Rocky shames the head of the loan company, Walter Fleming, into doing his patriotic duty to restore mail service to the area by lending Nugget money to repair his stagecoach. Shortly after they leave, Jim Boylan, the foreman of the local mercury mine, visits Fleming to discuss their recent delivery of mercury to Mexico, which made them $40,000 richer, and their plans to drive Nugget into bankruptcy so they can take possession of his house. That evening, before eating a homecooked dinner made by his niece Kathy, Nugget shows Rocky his new running water tap that Boylan recently installed, and introduces him to Kathy's fiancé, Lt. Dan Booker, who is stationed at the mine to oversee the delivery of mercury to the Army for the war effort. The following day, Nugget is again ambushed on his mail run, but Rocky, who has been following, captures one of the outlaws, Spec Matson. When Spec refuses to talk, Rocky lets him escape and follows him to the mine. Meanwhile in the mine's assay office, Boylan's men are completing a plumbing job that links to Nugget's kitchen sink. To smuggle mercury past Dan and the other soldiers, Boylan plans to pour it down the assay room sink and retrieve it at Nugget's, where it can then be taken to Mexico. To cover the loss, Boylan reports to Dan that a breakdown in the smelting equipment is decreasing the mercury output by twenty percent. When Dan tries to inspect the equipment, one of the outlaws throws liquor on him and starts a fight that is timed for the arrival of his superior, Maj. Seeley, who peremptorily relieves Dan of duty for drunken brawling. Later at Nugget's house, Rocky suggests that Boylan is behind Dan's troubles, and when Dan remembers the discussion about reduced production, Rocky guesses that Boylan is conniving to steal the twenty percent. Outside, Spec and his cohorts set fire to the stagecoach and draw Rocky out for a gunfight, but retreat from Nugget's and Dan's return gunfire. While tending a gunshot wound Dan received, Nugget and Kathy find quicksilver in the tap water. Rocky guesses that Boylan and his men are causing Nugget's bankruptcy so they can acquire his house for smuggling mercury out of the mine, and wonders if Fleming is also involved. To verify Rocky's suspicion that the sink in the assay office connects to Nugget's pipeline, they proceed to the mine. After Dan and Nugget distract the guards, Rocky sneaks inside, but is soon discovered by Boylan's men. In the ensuing fight, Rocky loses his government badge, which the thugs later find and report to Boylan. Realizing that Rocky is on to them, Boylan decides to cut his losses by having his men smuggle out all available mercury through the sink and retrieve it from a break in the pipe before it reaches Nugget's house. Still unaware that his identity has been discovered, Rocky wants to catch Boylan in the act of smuggling, so has Nugget pretend to put his house up for sale. Fleming, who agrees to alert prospective buyers, shows up that afternoon at the house when Nugget and Rocky discover that the water tap is not working. Offering to fix it, Fleming bangs on the pipe with a skillet to alert Boylan, which confirms Rocky's suspicions about his complicity with the outlaws. Dan sneaks out to get help from his Army buddies, but Fleming pulls a gun on Rocky and Nugget, and Boylan's men arrive to take them as hostages to the spot where the mercury is being loaded. Rocky stalls them by fighting until Dan arrives with other soldiers, who capture most of the outlaws. Boylan and Fleming escape, however, detouring to town for the $40,000 they have in the loan company safe, but Rocky follows them to the office, shoots Fleming and apprehends Boylan. Later, Kathy thanks Rocky for helping Nugget and for clearing Dan's name. Before riding back to headquarters, Rocky tells Nugget that he expects that the government will replace his stagecoaches.