Anything can happen on Nim's Island, a magical place ruled by a young girl's (Abigail Breslin) imagination. It is an existence that mirrors that of her favorite literary character, Alex Rover- the world's greatest adventurer. But Alexandra (Jodie Foster), the author of the Rover books, leads a reclusive life in the big city.
When Nim's father (Gerard Butler) 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.