The Land of the Silver Apples

The Land of the Silver Apples is a fantasy novel for children, written by Nancy Farmer and published by Atheneum in 2007. It is a sequel to The Sea of Trolls, second in a series of three known as the Sea of Trolls series or the Saxon Saga.
The title refers to the "silver apples of the moon" associated with the land of faerie in W. B. Yeats' poem "The Song of Wandering Aengus". The book received the Emperor Norton Award.

Plot summary

Jack and his companions take Lucy to a shrine where the demons she is believed to harbor may be cast out, but things go badly wrong. Lucy is abducted by the Lady of the Lake and Jack must follow her underground to the lands of the hobgoblins and elves. He meets Thorgil again and, with her and a new friend, Pega, must face tests beyond anything they can imagine. They must learn to see through the enchantments of the elves and to face still darker powers in the underworld.