Political unrest helps spawn and destroy a friendship between two schoolboys in this drama. In Chile in 1973, as the leadership of socialist president Salvador Allende was coming under fire from the nation's military leaders and the leaders of several powerful Western nations (including the United States), many in the country were inspired to address the issues of the vast gulf between Chile's rich and poor. Father McEnroe (Ernesto Malbran), one of the headmasters of an exclusive private school, decides to confront this matter by giving a handful of poor children a full scholarship. Pedro Machuca (Ariel Mateluna) is one of the new students, and while he and his fellows are picked on by the school's bullies, Pedro is a brave kid who stands his ground, and he's soon befriended by Gonzalo Infante (Matías Quer), whose rich parents live in Santiago's wealthy suburbs. Gonzalo's family is standing on shaky ground these days; his mother (Aline Küppenheim) is having an affair, and his father (Francisco Reyes) finds himself at odds with her increasingly right-wing political views. Gonzalo begins spending more time with Pedro and his family; he particularly likes Uncle Willi (Alejandro Trejo), who cheerfully sells flags to Chileans on both sides of the political fence, and develops a crush on Silvana (Manuela Martelli), Pedro's older cousin. But the political and economic differences that are dividing the country find their way into the school, leading to a rift between the two friends.