Nim's Island (2008)

Anything can happen on Nim's Island, a magical place ruled by a young girl's imagination. It is an existence that mirrors that of her favorite literary character, Alex Rover - the world's greatest adventurer. But Alexandra, the author of the Rover books, leads a reclusive life in the big city. When Nim's father goes missing from their island, a twist of fate brings her together with Alexandra. Now they must draw courage from their fictional hero, Alex Rover, and find strength in one another to conquer Nim's Island.