Tom D. Fitzgerald--better known as The Great Brain--has turned thirteen, and pretty Polly Reagan has put a spell on him. But when it comes to swindling his younger brother J. D., and all the other kids in Adenville, Tom hasn't changed a bit. The Great Brain is back one more time, and he's at the top of his form with his money-making schemes and getting into big trouble. As always, life is more exciting when this brain's around!