Billy Carter and two Mexicans, Cuteo and Estaban, are smugglers of opium which they bring across the border from Mexico into the United States. The authorities are unable to apprehend them, so "Pinnacle" Bill and "Cheyenne" Harry of the Arizona Ranger Service are sent to assist the sheriff, Dan Beckham, and the inspectors in their search. "Cheyenne" and "Pinnacle" put up at a Chinese restaurant. "Cheyenne" becoming suspicious of Wong Lee, the proprietor, and the Mexicans, shoots a hole in the floor of his room, apparently by accident. His room is directly above the kitchen in which Wong Lee, Cuteo, Estaban and Billy are conversing and plotting. Enlarging the bullet hole, "Cheyenne" is able to confirm his suspicions. However, he and "Pinnacle" wish to catch the smugglers red-handed and wait until that night when the law-breakers intend to make a trip across the border. Late in the night, as the smugglers are about to cross the river intersecting the two countries, "Cheyenne" and "Pinnacle" as well as the sheriff's party, begin to fire. Billy attempts to get away and is pursued by "Cheyenne." Harry overtakes the boy and when he discovers who it is, he allows him to escape across the line. Billy is the brother of Mary Carter, whom "Cheyenne" has always loved. "Pinnacle" then arrests "Cheyenne," but gamblers by nature, they toss up a coin to decide if the prisoner shall be jailed or freed. The coin, fortunately for "Cheyenne," falls "heads" up. He hands his Ranger badge to "Pinnacle" and rides across the boundary with Billy.