Mage Fire — C. Aubrey Hall

Mage Fire is the thrilling conclusion to The Faelin Chronicles series about a twin boy and girl, the children of a Fae mother and a human father, who discover a new destiny after their parents are murdered. They learn that their parents' cautious ways hid a lifetime of secrets, including Eirian, a magical sword that was buried on their farm. Their little sister has been taken by someone who wants that sword, and the ultimate power that comes with it. The twins-along with their friends, a goblin boy and talking wolf pup-must recover the sword and use it to save their sister.