Book Jacket
"The heart of the magic was sealed with Firefrost, the Weirdstone of Brisingamen
should Nastrond destroy the stone, then the magic will die away."
When Colin and Susan are pursued by eerie creatures across Alderley Edge, the wizard-- Cadellin Silverbrow--takes them to safety deep in the caves of Fundindelve. Here he watches over the enchanted sleep of 140 knights, awaiting the fated hour when they must rise and fight.
But the Weirdstone of Brisingamen is lost and the forces of evil are closing in. The children realise that they are the key to its return., but how can they defeat the powerful magic of the Morrigan and her deadly brood?