La corona dai sette smeraldi

Three bandits, plus a fourth who is immediately abandoned to the wrath of the mob, rob the church of a small Mexican village of a precious gold crown set with seven emeralds . Tex and Kit arrive in time to rescue the fourth bandit from the lynching and, thanks to his indications, they set out on the trail of the remaining three, determined to restore the crown to its rightful place.

In a secret valley inside the extinct volcano called Mount of the Vultures lives a colony of Aztec survivors who for generations have enslaved a tribe of Pima Indians to make regular sacrifices to the Sun God . This time they chose the daughter of the Pima chief and a boy from the outside world: Kit Willer . However, they have come to terms without the two fathers: a Tex determined to do everything and a slave leader now ready to rebel, who, supported by a "reformist" faction of Aztecs, will leave no stone unturned to save the two boys and overthrow the tyrannical rule of the High Priest.

This adventure is the latest in what we might call Kit Willer's "teaching cycle," a series of stories that saw father and son touring the American Southwest together.