What is the theme of Hector Munro's The Open Window?

The essential theme of his story is deception. Not everything is what it seems. Vera shows how her sweet and innocent nature is all but a front of her mischievious and slightly cruel character. Vera is extremly self possesed and muture beyond her years, her imagination is flamboyant but so overpowering it is almost as though she gives into it. Her quick thinking attitude is aided by her imagination to create her disturbing story to Mr Nuttel. Not sure if this helps anyone, jsut my view of how i see the story.