Gr 9 Up-Sixteen-year-old Arielle Delaney needs some sleep. Or so she thinksotherwise why would she be seeing ghosts? The hauntings start soon after her sister Casey's best friend, Perdita, drowns in a local lake, and a very Perdita-like image starts to appear. The ghost puts Arielle in a trance, whispers in her ear, scratches her while she's sleeping, and destroys her room at night. As the story unfolds, questions mount not just about Arielle's visions but about the death of the title character. Is the ghost trying to tell her something? Was Perdita's death an accident, suicide, or murder? Is Casey somehow involved? And when did Perdita's brother Tex become so hot? Arielle is eventually able to answer these questions, and what she discovers is surprising on many levels. Arielle is a sympathetic, likable, and realistic narrator, thanks to Gardner's keen ear for teen dialogue and understanding of typical adolescent behavior. As the protagonist navigates the unknown and explores the large space between right and wrong, she realizes nothing is perfect and life is messy. Secondary characters like Casey, Tex, Arielle's parents, and her suddenly distant best friend, Chloe, enrich the story. VERDICT An absorbing mystery with an appropriately untidy yet satisfying ending that will hold readers' attention throughout. Melissa Kazan, Horace Mann School, NY