Through the discoveries of the scientist, Dr. Morgan, a young Martian's astral body is projected into the body of one Harry Thorne on Earth, and from Earth to Venus, or "Zarovia," where the man of Mars becomes Prince Zinlo of the mighty empire of Olba. Zinlo is instructed by Morgan's fellow-scientist Vorn Vangal in the universal language of Venus and other skills. An attempt to kidnap Zinlo by Taliboz, a secret foe of the empire, forces him to flee in an Olban airship. He crashes in the empire of Adonijar, where his quarrel with Prince Gadrimel over the Princess Loralie of Tyrhana is interrupted by Taliboz, who seizes the girl. Zinlo and Gadrimel pursue Taliboz, and many thrilling adventures are encountered by Prince Zinlo.