One by one men rode into the black blotch of the canyon's mouth -- rode to a strange and fiendish death. Others, armed and vigilant, rode in to save them but they, too, never came back. Soon no man dared make the suidide ride. This was the sinister peril Jim Hatfield faced on his undercover mission at Massacre Canyon: Hatfield stood alone between Texas justice and a madman's shcemes to enslve the Border country--between discovery of the outlaw valley's secret and crushing defeat at the hand of a diabolica demon!