Every chapter teems with wholesome, stirring adventures, replete with the dashing spirit of the border, told with dramatic dash and absorbing fascination of style and plot. This is the story of Lieutenant Bucky O Connor of the Arizona Rangers, a lithe and fearless lawman called in to hunt down a gang of train robbers. Along the way he teams up with Sheriff Bear-trap Collins and three Mackenzies, including the spirited and lovely Frances Mackenzie, in an adventure that takes them into Mexico.