When Ali Mukbar and Jim Atkins started on their trek across the Yorkshire Dales it was just a fun thing. Till they found themselves battling to keep Princess Clyra Vergred from Space invaders determined to capture her to make impossible demands from her father the Emperor of Kharlor. Jim's father, a radio scientist, led the race to develop a Hyper-space radio to be able to contact him. But Jano, the brutal Rebel Leader, had his own scientists, technology - and all the resources of a FTL Battle Cruiser to block it and to beat off Earth's forces deployed to defeat him. Just when Jano thought he had won, Jim, Ali and others broke free. When he'd trapped Jim again and was about to laser him, Trigger, Jim's terrier, arrived like a thunderbolt. But Jano was still determined to grab Clyra in spite of the Emperor coming to Earth.