Prince Julian's quest for the Jewels of Power continues in the sixth book in the Westria series.
The King of Westria is dead, the land ruled by a regent. Prince Julian, the long-lost son of King Jehan, has returned to claim the crown. But he must first prove his right by finding and mastering the four jewels of power lost in the magical cataclysm that killed his father.
Julian has recovered two of them: The Earthstone and the Sea Star. Now he must survive the quest for the Wind Crystal.
Truly it holds one spellbound in the old meaning of the word - Andre Norton