Rodrigo Pla directs this social drama set in a privileged gated community in central Mexico City. La Zona, despite its affluence, is surrounded by miles of slums where people live in abject poverty. One night, three men from the slums break into the compound and, in the bungled robbery that follows, an old woman is killed. Her housemaid alerts the security guards, who kill two of the men; the third, a sixteen-year-old boy named Miguel (Maribel Verdu), manages to escape and hides out in the basement of an apartment belonging to the family of teenager Alejandro (Daniel Tovar). Alejandro, who has hitherto been primarily preoccupied with planning his birthday party, forms an uneasy alliance with Miguel - causing both boys to question the value systems on which their lives are based.