Strange things are happening on Earth. Not only are spaceships being sabotaged, by unknown persons, but space terminals are being bombed by a mysterious craft which vanishes into the stars on each occasion. What is the connection between these happenings, and the messages being received on Earth from the mysterious being who calls himself the Cardinal? All that is known of the Cardinal, is that he vanished from the Earth fifteen years ago, and is reputed to possess superhuman powers of strength and perception. Bob Newlyn is given the task of finding the Cardinal, and immediately he finds himself plunged into the most fantastic and hazardous assignment of his life.