An Unknown Enemy

The regent of Mexico City, Corona del Rosal, wants to weaken his main adversary in the presidential succession by getting rid of the National Security Directorate. Major Barrientos, the leader of the DNS, tries to strengthen its position and that of his boss by creating the perception that the student movement striking in Mexico City is a real threat, to then repress them violently.

Barrientos infiltrates guns among the students, to make them seem like a more threatening force to president Diaz Ordaz. Elsewhere, the CIA tries to influence the military leaders of the country to move forward with a coup and they reject their plans. Alicia, finally discovers who the government infiltrator.

Corona del Rosal convinces the president to use moles during the "March of Silence," a march organized by the National Strike Council, in order to put an end to the organization. Barrientos wants to thwart his plans by provoking a fight during the march. However, seeing how well prepared the students were, Barrientos has to put a stop to his plans and re-evaluate his methods.