Learning that a group of disgruntled landowners plan to seize the cuartel and free the political prisoners, Captain Monastario sets a trap to capture them, including Zorro's father Don Alejandro.

Faking Martinez's death, Captain Monastario again tries to use him to impersonate and disgrace Zorro by robbing a church, leaving Zorro confused as to who could be the impostor this time.

No sooner does the honest new commandante arrive than he is assassinated by a mysterious stranger who frames an elderly beggar for the crime and appears to be part of a larger conspiracy.

Sergeant Garcia receives a mysterious note from Zorro. The happy soldier reads that Zorro will give himself up. When he returns for his sword, it is gone, so he sadly returns to the cuartel without having captured his foe.

The King's tax collector and his nephew are stopped by conspirators, while on their way to Los Angeles. The conspirators threaten the men unless they cooperate, then they seize Morales' official documents.

With the death of the magistrado, the Eagle takes a more active role in his conspiracy to rule southern California. He sends two of his men, Quintana and Fuentes, to Los Angeles with a load of gunpowder for the weapons previously smuggled into the pueblo. The two men earn the wrath of the Eagle for suggesting that Zorro may upset the plan, and they fearfully head off on their mission.

The evil work of the Eagle takes a new turn when the commandante's wife, Raquel, visits Quintana and Fuentes and shows them an eagle feather, proving that she belongs to the conspiracy. She informs them the Eagle is furious over the loss of the gunpowder and that they must recover it if they hope to stay alive.

Sergeant Garcia and the other soldiers are amazed one morning when every musket seems to misfire. When they check their gunpowder, they realize it has been replaced with charcoal. A search of the cuartel reveals that all of the gunpowder has been stolen, leaving the post defenseless.

Raquel's ambitious plans for her husband appear to end when she receives a letter from him. She had been promised by the Eagle that he would be made governor of California, but her husband wants her to join him in San Diego, for he plans to sail back to Spain. Realizing the Eagle will not let her go, she tries to sneak out of the pueblo, only to be caught by Quintana.

Don Alejandro convinces all of the landowners to sign a document pledging their loyalty to the government, for he has become worried by the growing signs of possible civil unrest. He leaves a copy in the hacienda and takes the original to the capitol, intending to present it to the governor. Alejandro has barely left when Diego receives some unwelcome news. A new administrator has arrived in the pueblo and announced his decision to use the de la Vega hacienda as his headquarters.

An emissary from a foreign power has arrived in the pueblo to discuss plans to help the Eagle in his rebellion. George Brighton, the agent, warns Varga that there must not be any open resistance. His government wants an obedient colony, not one torn apart by internal battles. Varga promises to deliver control as planned, but he continues to worry about Don Alejandro and the other landowners who have pledged their allegiance to the King.

Diego overhears Varga telling his aide that the de la Vega hacienda is so comfortable he intends to make it his permanent headquarters. Knowing his father will soon return and would fight to the death to protect his home, Diego decides to try a risky plan to drive the Eagle out.

Another stranger arrives in the pueblo and travels to the de la Vega hacienda, intending to meet with the Eagle. Diego recognizes the visitor as Count Kolinko, an ambassador from an Eastern European country that has long been interested in controlling California. Since the Eagle has left for the pueblo, Diego manages to convince Kolinko that he is also part of the conspiracy. He almost succeeds in gaining necessary details of the plot.

Bernardo, who is keeping watch over Varga, is disturbed to see Garcia leading a patrol of lancers out of the cuartel. Even more disturbing is the sight of several strangers who drift into the Eagle's headquarters. When he tries to look inside, the gates are locked, so he rushes to warn Diego of the threat.