When the interplanetary vessel "Arcturus" sets out for Mars, an attack by a powerful alien ship leaves Steve Stevens and Nadia Newton castaway alone on the harrowing moon Ganymede. Love blossoms, but the pair are determined to escape and find any other survivors of the attack Using their scientific knowledge Stevens and Newton discover ways to reunite with the other Arcturus survivors--but are soon caught in a war to the death between two Jupiterian civilizations. Another space opera masterpiece from the creator of Lensman.