In a little airport near Santiago, Chile, live three airplanes, a papa plane, which carries mail over the Andes between Chile and Argentina, a mama plane, and a baby plane, Pedro. Pedro spends his days at flight school, hoping to grow up to be like his father. One day, his father has a cold in his cylinder head, so Pedro gets the call to cross the Andes, past the forbidding peak of Aconcagua, to pick up and bring back the mail from Mendoza. Pedro takes off, and the trip to Argentina goes well. Then, Pedro gets cocky, and the return trip goes badly. Will Aconcagua claim another victim? And what of the mail, does it get through?