A young boy is bored spending time with his dull grandma until he discovers she's an international Jewel thief.

We join Ben a year on as he is getting used to life without his beloved Gran. With the memory of their daring Crown Jewel heist still fresh in his mind, he is stunned to learn another spate of thefts are beginning to occur - with all the clues pointing to The Black Cat, better known to Ben as Granny!