Rosie hasn't been to Earth since she was 3 years old. For 7 years she's been living on the moon base with her scientist parents-and only one person her age-a boy named Robert. Rosie is planning lots of fun times for her vacation with her cousin Jenny on Earth. She and Jenny are going to be best friends But her plans go wrong from the start-and things get worse when she meets Jenny. Jenny has turned into someone very strange. As Rosie tries to solve the mystery of Jenny's weird behavior, she learns the secret of true friendship-and some secrets about herself Set in the not-too-distant...