Ben Hart, the youthful mining expert, arrived at Red Rock and promptly sought out pretty Mabel Whitaker and her mother, who had inherited a map purporting to lead to a gold deposit. Ben made an appointment to look at the deposit and did so - quite unaware that Jim Halliday, with two bad pals, kept close watch of his every movement. They met him on the road going back and remarked that it was a bad town for experts, to which sully Ben merely smiled. That night Mabel was awakened by a scratching noise. Rising from bed she seized a butcher knife and hurried into the other room. A hand was slowly appearing through a freshly made opening under the cabin. Only the ghastly arm could be seen, but in that fleeting glance Mabel saw an American flag plainly tattooed on the outstretched arm. Without an instant's hesitation she plunged the knife through the arm - there was a howl of pain, hurried footsteps and all was silent again. Next morning when Ben called, he was told of the nocturnal visit. He quietly mounted his horse and rode off in the direction of the claim. In the bushes he saw Halliday standing, with back toward him, an outstretched bare arm resting on a convenient tree trunk. Ben drew his gun, Halliday faced quickly about and a few minutes later was safely lodged in the local jail. Then Ben rode back to the Whitaker cabin as his thoughts turned toward softer things.