Intercepted by the Mexican soldiers furious because of the bloodbaths, Tex and El Morisco are jailed in Casas Grandes. When they manage to escape, here comes Montales to get them out of trouble! One of Tezcalipoca’s Jaguar Men, captured during the attack on the city’s barracks, has gotten free: at the end of a bloody clash, the monster is killed and the feline spots that covered him disappear as if by magic! Tex and El Morisco decide to go the San Diego mission to find the missing part of the Aztec codex taken from Tezcalipoca, before the human beasts get there!