Raven goes to live with Professor Young and his wife. After he puts up a picture of a raven in his bedroom, he explains to Mrs. Young the origin of his unusual name. That night, Raven looks through some of the professor's books, and learns that the mysterious bird that accompanies him is a merlin...
Raven is now involved in the professor's reserach into the legend of King Arthur. After studying the professor's plan of attack against the government's proposed nuclear plant, he too becomes convinced that it should be constructed elsewhere, but the caves have a surprise for him.
With the help of local reporter Naomi Grant, Raven makes an astonishing discovery; the Arthurian caves each have a symbol, and together the symbols form the zodiac. One sign is missing - that of the dragon, once the sign of Sagittarius. Racen spontaneously provides the missing symbol, but an ominous rumbling can be heard...
A cave has collapsed and site manager Bill Telford is trapped inside. A rescue team is called but Raven insists on returning to the cave to try to save his friend. The drilling proves difficult - but can Naomi's knowledge of astrology help the rescue team save Bill?
With the campaign against the government's plan for the nuclear plant gaining momentum, a minister arrives to try and sway public opinion. When Naomi is offered an opportunity to work in television, Raven senses that he is losing her. The professor gently tells him that Naomi was not meant for him; his destiny is very different.
The official inquiry hearing in the council chamber finds the forces in favour of the government far stronger than the opposition, and Raven and Naomi realise that they must produce convincing evidence. As events in the chamber take a tragic turn, Raven accepts his destiny.