One summer's night in Buenos Aires, a mysterious deadly snowfall wipes out most of the population and leaves thousands stranded. Juan Salvo and his friends embark on a desperate struggle for survival. Everything changes when they discover that the toxic snowstorm is only the first attack by a foreign army invading Earth. The only way to stay alive is to join together and fight. No one will survive on their own.

The series is the first screen adaptation of the iconic Argentine sci-fi graphic novel El Eternauta (The Eternaut), written by Héctor G. Oesterheld and illustrated by Francisco Solano Lopez, which was first published in 1957.