Life is already complicated enough for 12 year-old Summer Patefield when she is selected to attend Green Valley Tennis Academy for the next 8 years to play and excel at tennis. Green Valley is well known around the world for producing the most excellent tennis players. However, Summer quickly realizes that talented tennis players isn't the only thing Green Valley holds; it is full of secrets. Dark secrets. When Summer's senior friend, Ingrid, disappears with the rest of the seniors after graduation, Summer is determined to find out what is behind this horrible mess. First step: Stealing Head Master Delbert Bergamine's keys to The Hollow Delves.