The latest craze is 'octopus dare' and junior computer brain of the year competition. Dinah is a natural contender, but her behaviour becomes very odd. Could it be that the evil headmaster is up to his new tricks in a bid to take over the world?

Three of the Brains have disappeared, along with Ian. Dinah begins to catch on to what is happening, and everything depends on SPLAT getting to her. Then there's the matter of the booby trap to consider.