Striking where least expected, the outlaw band known as the Faceless Riders have been spreading a trail of terror and death along the Rio Grande, throwing the whole territory into a panic - and the toll from their guns is overflowing Boot Hill. As ace undercover Ranger Walt Slade rides into the Border country, he knows that only one man can rod a gang so ruthlessly - his bitter enemy Veck Sosna, the cleverest, most notorious outlaw he's ever faced, and who Slade's been pursuing across Texas. The stakes are high: if he doesn't beat Sosna, the whole Border country will crumble from law and order into the chaos of gun justice. Slade knows, too, that if he loses this battle, it will be his last. For there is another tombstone waiting on Boot Hill, marked with an S - Slade or Sosna!