Lost Shadow. The Neverwood Chronicles, #3

Not all shadows are monsters. And some were never meant to die. Wendy is on a quest for vengeance after Hook kidnapped the lost boys and destroyed their school. Stuck as a shadow, Peter's body is weakening because each time he dies and regenerates, may be his last. Meanwhile, Wendy is running out of time to track down Hook, save the boys, and rescue Peter before he's lost as shadow forever. But a surprising clue leads to the mysterious island where it all began.
Neverland. Right when they believe the nightmare is over, they find the game is just beginning.