Mr Grunt's a man with a mission.

He has to get a Person of Great Importance (or POGI) to someone called Mrs Bayliss by the twenty-fifth. Alive and well. And he can't tell anyone more than that, not even his lovely wife, Mrs Grunt, because there will be people trying to snatch the POGI and so the POGI must be transported in secret. It's an exciting adventure, but what interests Mr Grunt most are the silver coins he's been promised at the end of it.

The Grunts' stolen son, Sunny, has a few questions. Who is the big-earringed cyclist? Why does the POGI have to wear a barrel all the time? Is Rodders Lasenby a lovely person or simply the rudest man on the planet? And how long will it be before they find themselves All At Sea?