The ancient underground caves were in danger. They were going to be filled with atomic waste.  But forces were at work to save the sacred ground – forces from another time. What were the mysterious symbols in the caves and what was the connection with King Arthur? Could Professor Young the archeologist save the cave complex, and why did the merlin suddenly appear?  Raven, on probation from Borstal, found himself caught up in these strange events and began to realise that the future of the caves depended on him.  From the ATV series. Cover photograph shows English actor Phil Daniels as Raven. Illustrated by Les Matthews.