Three postal planes, those of Argentina, Chile and Paraguay, are returning on a night flight to Buenos Aires. There, the correspondence they carry will be moved to the plane which will take it to Europe. The director of the postal airline, Riviere, waits anxiously on the airfield of Buenos Aires for the arrival of the planes and, during the course of that night in 1930, he finds himself reflecting of problems he had never before considered. He realises that little by little he had been putting off his old age for when he had time, which makes his life pleasurable. As if at some point he could have time, as if at the end of life one could achieve that imagined peace. But peace does not exist and perhaps neither does victory. The definitive arrival of all the post does not exist. The first to land is the Chilean plane. Its pilot, Pellerin, has had to overcome a storm in the Andes. But he is not boastful about it. When Riviere, congratulating him, wants to know how he did it, the pilot answers with the precision of one who sees it as just one more unforeseen event, part of the job. For Fabien, pilot of the Patagonian plane, and his companion the radio operator, the situation begins to complicate itself. The first whirlwinds of the far-off storm begin to hit the plane. Riviere, over the transmitter, follows the heroic struggle of his men determined to complete their mission. He never ceases to give orders meant to help them, and in the midst of his growing concern, he reveals in his attitudes and responses various aspects of his personality. 'Am I fair or unfair? I don't know,' he recognises, 'If I punish, the damages are less. Man is not responsible, it is a dark power which can never be caught unless the whole world is caught. If I behave justly, every night flight would be in danger of death.' Of inspector Robineau, who supports him in his work, and is also part of the management, he thinks that thanks to his lack of intelligence, he can be of great service, for, if he does not think, he cannot make mistakes. With regard to his subordinates, he thinks, 'These men are happy because they love what they do and they love it thanks to my hardness'. But this does not exclude a certain measure of sensitivity: 'To be loved you have only to be compassionate.
I am rarely compassionate, or at least I hide it. However, I would love to surround myself with friendship and human sweetness'. Because, in spite of the harshness with which he treats others and of some rulings which, as well as injust, are absurd, in that struggle, a strange brotherhood linked Riviere and his pilots. They were men in the same boat, feeling the same desire to win. Before the storm which envelopes the Patagonian post in its growing fury, Riviera thinks that any possible disaster could damage him. Conscious of his responsibility as director of the airline and sole defender of the night flights, he has telegraphed the police of more that thirty provincial cities to ask for details of the state of the sky. Alarmed by her husband's delay, Simona Fabien calls asking to speak to the director. And, not receiving a satisfactory answer, she presents herself before Riviere. She soon realises the pointlessness of her visit. Nothing can be done except to wait. 'Also for this woman the recent death of Fabien would start tomorrow; in every act now vain, in every object, Fabien would slowly abandon his house'. Then, the inevitable happens. The Patagonian post plane is thrown about by the storm. The Paraguayan plane lands without any problems. Its pilot is informed by the European pilot that Fabien has disappeared. Few of them speak; a strong brotherhood exempts them from pat phrases. Moments later the European post sets off. Riviere, for whom the most important thing is the fulfilment of his duty, thinks that if he had delayed just one flight, it could have meant the end of the night flights. And, while the plane climbs, he slowlo his work.