In Mexico 1972, Romo, a government agent, tortures a young member of the urban guerrilla, in a clandestine detention center. After a lot of resistance, the young man finally confesses who is helping them: a friend of the agent. Romo hides this information and looks for his friend. While confronting him and accusing him of treason, he starts to have doubts about his ideological stand. They will soon have to encounter each other again under new circumstances.
