Secret in the stone

Summary/Review: "Claire Martinson and her sister Sophie have decided to stay in Arden--the magical land they discovered by climbing up a chimney in their great-aunt's manor. If what they've learned is true, the sisters are the last descendants of the royal family, and only a true heir of Arden--with magic in her blookd--can awaken the unicorns. Since Sophie does not have magic, the land's last hope rests on Claire. The sisters journey to Stonehaven, a famed Gemmer school high in the mountains of Arden, so Claire can train in the magic of stones. As Claire struggles through classes, Sophie uncovers dangerous secrets about the people they thought they could trus. With Arden on the brink of crumbling, can Claire prove she is the prophesied heir and unlock the magic of the unicorms before it's too late?"--Provided by publisher.