Virgillius Salucci travels with his scientist friend in a torpedo-like ship of the latter's invention to the North Pole and beyond, arriving in a clement lost world where they sight what seems to be a counter-Earth. They are taken by members of a primitive tribe to the city of the Centaurians, who display their much advanced technology and science, and who inform the visitors that the world in the sky is in fact the tenuous aftermath of a destroyed planet. Salucci falls madly in love with the beautiful princess Alpha Centauri while he and his friends explore the strange world she inhabits.

Originally published in 1911, this previously rare book is an early example of American science fiction.