One morning the townspeople of Dull-on-Sea wake to find that their town is overrun with rats. Big rats, small rats, fierce rats, hungry rats - it is an infestation! Just when everyone is at their wit's end, a nautical stranger who plays the pipe turns up and offers to get rid of the rodent problem - for a fee. Once that rats have gone, the greedy mayor refuses to pay - so the Pirate Piper plays an enchanted tune and leads the children away.

It's up to Matilda, Jim and Nugget to save their friends.