La Sierra is the most violent barrio in one of South America's most violent cities, Medellín, Colombia. Like the nation itself, the neighborhood exists in a state of perpetual civil war, with the cocaine trade an active participant. As the ranks of rival gangs are killed off, their members grow ever younger. Edison, 22, is the old man on the block, a father of six. Jesus, 19, can feel death calling him. Cielo, 17, is already a widow. This acclaimed documentary chronicles one year in their lives.