The Eternaut

The story begins with the comic's author, Oesterheld, appearing at the start, as he writes late at night. He is interrupted by a mysterious man who introduces himself as Juan Salvo, who then narrates his story. This framing sets the stage for the unfolding narrative about an alien invasion from Salvo's perspective.

Salvo, his wife Elena, and daughter Martita are depicted living peacefully before a sudden, mysterious deadly snowfall covers Buenos Aires. The snow wipes out all life upon contact, but the family survives by staying inside their fully sealed home. Salvo is shown playing cards with friends at the time of the snowfall.

Polski, one of Salvo's friends, attempts to return to his home out of concern for his family. Tragically, he succumbs to contact with the snowflakes shortly after leaving the safety of the house. This event highlights the deadly nature of the snowfall that endangers everyone outside.

Realizing the chaos caused by the snow and the threat of further danger, Salvo and others prepare insulated suits to venture outside. A young boy, Pablo, joins them, and they plan to gather supplies. Meanwhile, some survivors like Elena and Martita stay behind, trusting the safety of their home.

An improvised army is created to combat the catastrophe, joining Salvo and others. They face giant beetles controlled remotely by an alien known as 'Hand,' who commands an invasion force. The army establishes a base inside the River Plate stadium, establishing a defensive position against the alien devices.

Salvo teams up with Franco, a metal worker, to gather intelligence. During their reconnaissance, they discover that the beetles are controlled by unseen aliens through devices on their necks. They identify the 'Hand,' an alien with multiple fingers, as the controller of these beings and other affected survivors.

The army is lured into a trap at Plaza Italia, where they are attacked and decimated by giant creatures called 'Gurbos.' Only Salvo, Favalli, and Franco escape the slaughter. They continue seeking the main invasion force, risking their lives against overwhelming odds.

The survivors locate the primary invasion force at the Plaza del Congreso. They successfully blow up a dome housing the aliens known as 'Them' and manage to escape. During this chaos, Pablo and the historian Mosca are separated from the main group.

After escaping the destruction, Salvo, Favalli, and Mosca capture a spaceship. In the process, Salvo accidentally activates a time machine, which transports him to a pocket universe and separates him from Elena and Martita, who are stranded elsewhere in time and space.

Using the spaceport's advanced technology, Salvo learns to navigate between different universes and timelines. This ability explains his unexpected appearance at Oesterheld's house and the layered nature of the story, blending different periods and realities.

Realizing he is in Buenos Aires just years before the invasion, Salvo rushes back to his home to reunite with Elena and Martita. They manage to restore a stable time loop, effectively preventing the invasion from occurring in their original timeline, though Salvo’s narrative remains a recounting of future events.

Having returned to his original timeline, Salvo and the narrator comment on the futility of changing the future. Oesterheld, the comic's creator, reflects on the power of storytelling in confronting inevitable tragedies, as he decides to write about the invasion despite knowing its grim outcome.