Doctor Who: Code of the Krillitanes

"e;I blame those new Brainy Crisps. Since he started eating them, he's been too clever by half."e;Can eating a bag of crisps really make you more clever? The company that makes the crisps says so, and they seem to be right. But the Doctor is worried. Who would want to make people more brainy? And why? With just his sonic screwdriver and a supermarket trolley full of crisps, the Doctor sets out to...