The Robilliard family travel across on the ferry to Poole in the summer holidays. P’tite Jeanne joins them and causes all sorts of chaos delaying the ferry.
When the family eventually reach the mainland they drive down to Cornwall to see their cousins. They all go to the Eden project for a day out.
P’tite Jeanne meets up with her Auntie, Joan the Wad, Queen of the Cornish piskies. Together the two fairy folk cause all sorts of mischief in the Rainforest dome, Mediterranean dome and the core.
A small human child needs help at the end of the story and the fairy folk, who have kind hearts, save the day.