The Third Key: The Alaesha Legacy, Book 1

Edith Myers has just about had enough. Her first day at a new school and she already has an enemy - Dana Blake. Head cheerleader, tormenter, typical prom queen. But when Edith discovers a strange key, she finds them both embroiled in an inter-dimensional war. She and Dana must find a way to work together, or it could spell the end of the other world, and theirs.