Emlyn's Moon (Nimmo, Jenny. Magician Trilogy) by Jenny Nimmo
Rating:This is the second book in the magician trilogy. And although it has an absolutely wonderful story, I don't like it quite as much as the first book, because Gwyn isn't the main character in the story. Gwyn still does amazing magic, but the story is told from Nia's viewpoint.
Description:When Nia's family moves away from the mountain and into town, she feels as if a part of her is missing. Once in town she makes an unlikely friend in Emlyn, a boy she has been warned to stay away from. The villagers think that something awful happened to Emlyn's mother, but Emlyn claims she just lives in the moon. Nia and Gwyn must use magic to solve the mystery of what really happened to Emlyn's Family.