It's 1873 and the disbanded Texas Rangers have been replaced by the corrupt Texas State Police. Steve Lanning arrives posing as a wanted outlaw to get in with them in his attempt to have them replaced. His inside work helps the Durango Kid break up the State Police raids but he is in trouble when his secret identity as Durango becomes known to them.
Quick on the Trigger was Charles Starrett's second "Durango Kid" picture for 1949. It all begins when ousted sheriff Steve Warren (Starrett) is put on trial for the murder of heroine Nora Reed's (Helen Parrish) brother. Steve is innocent, of course, but he doesn't stand a chance against prosecuting attorney Garvey Yager (Lyle Talbot) -- especially since Yager is the real killer.
A major Indian uprising is expected and Wyoming military posts are alerted. Colonel Dennison (Fred Sears) is meeting with Chief Eagle (Shooting Star) and his son Running Wolf (Jay Silverheels) when Chief Eagle is mysteriously shot. Steve Holden (Charles Starrett), an agent for the government peace commission, with the aid of a wandering shoemaker, Smiley (Smiley Burnette), discover the troubles and the Chief's murder have been instigated by Cronin (Bob Wilke), the regimental scout, for personal gain for he and his gang of outlaws.
The outlaw gangs are robbing the railroads and the Rangers cannot follow them when they move to New Mexico. So Kip decides to take a vacation to New Mexico and, as the Durango Kid, bring Cass and his gang back to justice. But Cass and his gang are killed at the bank in a double cross and Kip must still find the loot. For this, he enlists the help of Tex and Grubstake, although Grubstake does not know it.
Charles Starrett plays lawman Steve Forsythe in Ridin' the Outlaw Trail. Somewhere along the line, of course, Steve is obliged to don the mask of The Durango Kid, mysterious righter of wrongs. The "wrongs" in this instance include the theft of $20,000 in gold, and the "kidnapping" of a blacksmith's forge! Jim Bannon, who only a few months earlier had played the heroic Red Ryder, provides the villainy in this fast-paced "Durango Kid" entry
Silver is being smuggled across the border and the secret passage goes through Betty Long's basement. When Steve arrives he gets tangled up with the rustlers who are now going to have the Durango Kid to contend with.
Charles "Durango" Starrett and his pal Smiley Burnette go after smugglers. Our heroes travel incognito across the Mexican border to beard the leader of the gang in his den.
The plot finds Steve/Durango attempting to capture ex-Civil War guerilla fighter Miller (Trevor Bardette), who may be the man who's been going around knocking down telegraph wires.