The student strike at the National University of Mexico City has been going on for more than a month. Roommates Sombra and Santos stay in their dorm, spending their time fantasizing about girls on the radio, teasing their neighbors' daughters, and helping them steal electricity. The arrival of Sombra's younger brother Tomas interrupts their idle life - his mother persuaded him to go to the city to take shelter because he threw a water balloon from the rooftop and hit his neighbors and babies. The three decided to set out to find Tomas' idol, the legendary rock singer Epigmenio Cruz. Along the way, they passed through the slums, the rioting campus, and arrived at the bustling center of Mexico City...