A young girl disappears from Polzeath on the Cornish coast, and soon afterward, terrorists threaten to guide a comet to explode on impact as it strikes the heart of Britain. James, Jo, and Jake (alias the 3Js) make some startling discoveries close to where the girl has vanished. Can they and the legendary Knights of the Round Table triumph against the power of an evil sorceress and her hideous creatures of the underworld?