Synopsis: The epic voyage of the Space Star Silver Streak has come to an end. The survivors of the tragic destruction of Earth live contended lives on the colonies the Silver Streak spent so many years establishing. Old friends have gone their separate ways. But then an awesome force enters our galaxy. Emitting radiation more powerful than anything ever seen in our galaxy before, it sweeps away entire planets in its path. Seventeen colonies are wiped out. Those who manage to escape in time are stranded in space in slow-moving vehicles. Only the Space Star Silver Streak and Captain Richard Cameron stand a chance of rescuing the survivors and dealing with this awesome menace. But Hyron worlds have been destroyed too . . . and Mordrax is on his way to a deadly rendezvous with his old enemy!