In the middle of the 19th century, in a fort on the Pampean frontier, the Carbajal family -father and son- are left abandoned in a cell after a raid of Indians ravaged the place. Miguel, with very little strength, tries to keep his father, who is seriously wounded, alive.

The story of Maxi Herneston, whose life is far from perfect: he works as an employee in a local video store; he has an older brother who tortures him day and night and a mother obsessed with sex. But these circumstances become minor details when he accidentally ingests a virus from outer space that will make him feel incredibly sick and, in the final instance, will force him to defecate five aliens who at first seem friendly but who later turn out to have their own plans regarding the boy and the future of the earth.