Deputy U.S. Marshal Custis Long's been sent down El Paso way to break up a smuggling ring dealing in human cargo--Chinese laborers. Going undercover using the alias Nathan James, Longarm waits for his moment to catch the smugglers red-handed crossing the Rio Grande.
While in town, Longarm is befriended by a brother and sister. Bob Temple is a one-armed man who wants "Nathan James" to give him a hand in a bank robbery south of the border. His lonely sister Bobbi has other plans for Longarm...which won't require him to wear his gun belt.