Doubleborn — Toby Forward

This is the third novel in Toby Forward's "Flaxfield Quartet". Tamrin doesn't like being at the Canterstock College for Wizards, but when the tailor who sent her there arrives to take her away she knows that she should not go with him. She sets off to find Sam, only to find that their mutual enemy, Ash, has been waiting for her to lead the way to Flaxfield's old apprentice so that she can use him to help her to escape from the Tower in which she is imprisoned.