Nugget comes back from school with a drawing of a beautiful mermaid, but Jim laughs and takes him on a trip to see a real mermaid.

Jim and his family seem to have fallen victim to a curse, and decide to go back to sea; if not, they are in danger of being turned into landlubbers just like their house, which is magically cleaned and nicely decorated in their absence.

Jim and his family seem to have fallen victim to a curse, and decide to go back to sea; if not, they are in danger of being turned into landlubbers just like their house, which is magically cleaned and nicely decorated in their absence.

In Dull-on-Sea, Matilda finds her quiet life commandeered by the arrival of an eccentric pirate family, the Jolley-Rogers, and she quickly befreinds them.

Matilda tries to take a look inside the pirates' ship, but accidentally sets the Black Hole loose, which then rolls all the way down the street until it crashes into the school, which threatens to get the pirates evicted from the town.

To his horror, Jim discovers his ancestry isn't with infamous pirates, but from Francis Flunky, an expert on etiquette; Jim then tries to behave as an upstanding, polite young boy.