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!

Over one intense day, the devoted head teacher of a last-chance reform school strives to keep his students in line while facing pressures of his own.