Film based on the life of Dr. Salvador Mazza, who, with a group of professionals, conducts an investigation to discover the antidote to a mysterious illness whose carrier is a nocturnal insect. A Mazza was regarded as the first doctor who fought the deadly Chagas disease in Argentina.

The film focuses on the journey of General Juan Facundo Quiroga, with a very compromised health, to the north in order to resolve the conflict between the provinces of Salta and Tucuman.