The Valley of the Lost

The 7th book in the Deltora Quest series 

Leif, Barda, and Jasmine have almost reached their goal. Six gems gleam in the belt of Deltora. Now the last one must be found before Deltora can be freed from the evil shadow lord.

the companions have faced many terrors before. But the worst is yet to come. They are about to confront the dark mysteries that strength and courage alone cannot defeat. If they fail, their quest will be destroyed. . . And they will remain for ever trapped in the shrilling mist of the valley of the lost.