Santiago, Chile, 1973: Pedro Machuca is a poor boy of tribal descent, brought into an upper class private school during Chile's brief socialist era. Gonzalo, the well-to-do boy seated a row ahead, befriends Pedro against the bullying will of his classmates. In so doing, he discovers a raw, thrilling but wildly complicated world outside his own previously sheltered homelife. Pedro's fierce, attractive young neighbor Silvana by turns mocks Gonzalo's pampered background, only to fondly lead both boys in a number of kissing games. All around them, Chile drifts towards civil war. The enormous rift between Gonzalo's comfortable household and Pedro's hard-scrabble life a few miles away in an illegal shantytown ultimately becomes impossible to bridge, once the bloody military coup of September 11, 1973 erupts. All three children suddenly face moral tests far beyond their young capacities.