La stirpe dell'abisso

An ancient Mayan legend tells that, before humanity, the gods made other tests of creation, but the race of serpent men was so horrendous that it was confined to the eleventh abyss of the hell of Mitnal... When a friend of the Morisco, Doctor Palacio, shot to death by mysterious men in black, leaves him an enigmatic diary, the curandero of Pilares asks Tex for help and, in the company of the four incomparable pards and the faithful Eusebio, sets off towards the depths of Mexico and towards unknown horrors...