Eric's in deep trouble. If he doesn't pass a tricky test at school he'll have to spend the next thee weeks taking extra tuition and, worst of all, that means he'll miss the final of the Junior County Football Cup! But then a mysterious parcel arrives form his Auntie Rose in South America. Inside it, Eric finds "The Striped Horror", a weird looking, even weirder smelling, jumper, and a note explaining that this magical jumper will increase the brain power of its wearer. And when Eric gets 100% on his test he doesn't need any further convincing.
Hailed as a genius, Eric suddenly finds himself thrust into the spotlight, competing in Junior Brain of the Year - on television! Things are going well until an accident means Eric must continue the contest without The Striped Horror and risk making a fool of himself in front of thousands of viewers!