Stranded on the planet Venus, known as Amtor to its inhabitants, Earthman Carson Napier has faced countless perils to win the hand of the courageous Duare, his beloved princess, and to be bestowed with high honors and the title of prince in the powerful nation of Korva. But when a new threat strikes from out of the skies, Carson discovers his own arrival on the planet years ago may have unknowingly led the mysterious enemy to attack.