Don Alejandro tells Diego he's received a letter from a friend in the capital telling him that the new commandante, Capitan Juan Ortega, has the reputation of being an honest and fair man. When Ortega arrives, he doesn't act that way. He treats Sergeant Garcia with contempt and is openly arrogant toward the civilians. The reason for this is revealed when Ortega meets the magistrado and informs him that the real commandante has been ambushed and murdered, on orders of the Eagle.

The plans of the fake commandante and the magistrado go awry when Ortega spots Diego talking to Rosarita Cortez, a childhood friend who has recently returned from the capital. Ortega fears she will recognize him from her journey, for it was during that trip that he murdered the real Ortega and assumed his identity. Bernardo overhears the two villains planning her death, and notifies Diego.

Another agent sent by the Eagle arrives in the pueblo, this time smuggling jewelry to finance the conspiracy. Carlos Murietta, an Argentine who is contemptuous of the locals, particularly Sergeant Garcia, visits a tannery run by Jose Mordante. The two men discuss the disposition of the gems, including a famous piece known as "The Cross of the Andes", which were stolen from churches in Argentina.

Expecting another shipment of jewels, Murietta goes to inspect the tannery where they will be stored. There, he spots Pasqual, a peasant who lives there, and whips the old man until he leaves. The shipment arrives accompanied by Dolores Bastinado, recently arrived in the pueblo, who attracts the attention of Sergeant Garcia.

Determined to find the missing jewels, Diego and Bernardo visit a local padre in the hopes he can assist them in their quest, but the trip is to no avail. Later, when Carlos Murietta complains to Sergeant Garcia about the missing trunk he had stored at the tannery, Diego is convinced more than ever that the jewels were hidden by Mordante before his death.

Another shipment of stolen jewels arrives in the pueblo, and Dolores Bastinado unwittingly allows her brother, Pogo, to deliver the cargo to the Murietta brothers. The trunk slips and breaks open, and Pogo spots several of the gems. He realizes the men will try to kill him to protect their secret, but he is seized before he can flee. The Muriettas bind and gag him, then hide him when they hear Sergeant Garcia arriving.