Something wicked

"Harper is dealing with too many new changes in her house. Her cousin, Leo, is now living with them; her sister, Kelly, has started working at a local makeup store, Jeune; and Harper's spirit hunter abilities have grown increasingly more powerful and uncontrollable, making her a target for possession. But when Harper and Dayo uncover a dangerous plot to steal youth from millions of innocent people, Harper must use all her powers to destroy an ancient evil and save her sister. Can our intrepid spirit hunters rescue Kelly before it's too late?"--From the publisher's web site.