Wish - Michael Tolkien

Farmers in their alpine valley are haunted by Fngler, a cunning old enchanter, who ruins their lives by using an ancient wishing chain of powerful stones to spoil crops and steal children, cows and goats.
Young Berwald and his sister Clara set out, without their parents knowing, to climb into the next valley, seize the chain, free their neighbourhood of fear, and wish for whatever they want. But they soon learn that the wild world beyond their home is full of strange forces - some good, some dark and twisted - and almost every wish they make adds new complications and disagreements.
Who can rescue them from this fearful and dangerous adventure? Before Adam, their angry and worried father, can reach them, he must learn to follow seemingly useless leads, and to listen carefully to the tale that lies behind the villain's bitterness.
A timeless fantasy tale given new life and enchantment in this vivid retelling in verse.