Daphne Mayne and the Hounds of Magic - Chronicles of Wydoria, #2

Just when Daphne thought she could forget about magic, that it had nothing more to do with her, an elf crashes into her life and turns her world upside down. The elf - a girl Daphne's age - needs the power of the Wightstone to save her people. Reluctantly, Daphne agrees to help, but their journey quickly becomes treacherous. Pursued by the Consistorium's Hounds of Magic, the two girls face danger at every turn.
To make matters worse, the Wightstone loses its power, Daphne's magic disappears, and she falls ill with a mysterious sickness. The pair rely on their courage and wits to survive as Daphne's condition worsens, and the hounds of magic draw closer. Now, the fate of the world rests on the shoulders of an elf whose strength and intelligence are all that stand in the way of the forces of evil. Will she save both Daphne and her people, or will darkness triumph? You will love this book if you like the Song of the Lioness, or The Immortals quartets by Tamora Pierce, or His Dark Materials by Philip Pullman. Contains mild violence, threats and references to death