Raven, a 15 year old Borstal boy, is released on probation to live with Professor Young, an archaeologist immersed in research into Arthurian legend, and his wife, an amateur ornithologist. The professor is working in deep underground caves whose carved symbols suggest that King Arthur may have used them as a hiding place, and Raven is intrigued by his belief that Arthur was not one man, but a succession of chiefs.

The Professor's reserahc is in peril as the government palns to build a nuclear waste reprocessing plant on the ancient site. As Raven is drawn into the battle to save the caves he begins to understand its mysteries - and the brightly coloured bird that has accompanied him on his journey holds the key to the discovery of his own unique destiny.

Made by Associated Television (ATV) for the ITV Network in 1977.