Gaspard is the last man on Earth. Zeria, his grandson, is the first to be born on Mars. Gaspard tells him about his life, in the hope that Zeria will come to see him... Zeria would be the first human being to return to Earth...

The year 2056. On the eve of his hundredth birthday, Gaspard is about to die. He's writing a video letter to Zeria, his grandson, whom he has never met. Indeed, following the great migration of humans away from planet Earth, Zeria is the first human being born on Mars.