Tex receives a call for help from the commander of Fort Wellington. When he gets there, Colonel Cabot tells him the story of the mysterious Indian woman Yogar, the golden idol she stole ( Xipe or Anauak ) and the mysterious murders that happened in the fort. Asked to solve these questions, Tex decides to take the golden idol into his hands and find out what's behind it all.
As a result of taking the treasure of the Indios Blancos (from the previous adventure "Il mistero dell’idolo d’oro"), Mexico invades the southern part of Texas. Tex joins the regular American forces who manage to stop the Mexicans and the conflict turns into a guerilla war. Tex is tasked with uncovering a Mexican spy.
This is where he finds a suspicious magician: Steve Dickart accompanied by his sister.
