Raven rise - D.J MacHale

Bobby Pendragon is trapped… with a single, massive explosion of Tak the entrance to the flume on Ibara was destroyed, sealing off any means of escape for Bobby, and his nemesis, Saint Dane. Even though he had given up all hope of ever returning to his old life, Bobby was ok. He felt certain that by burying the flume, he had ended the war, and that after so many battles and so much sacrifice, Halla was finally safe.
He was wrong…
The final battle for Halla was already underway… territories were changing, nothing past, present or future would ever be the same. Unable to contact Pendragon, Mark and Courtney find themselves faced with an impossible task of defending their home against the inevitable wave of evil that Saint Dane has set in motion. The next target was set, but there was only one thing missing - Bobby Pendragon!