This time, they travel on holiday with Aunt Thea to Summer Island. There they meet Eddy who is an expert on all the challenges they can face on a magical island. It is rumored that a sea worm has been observed in the fjord, and it will not be long before the energetic sea worm expert Blegen shows up, with his strange devices and instruments. It will be an exciting summer holiday with friendship put to the test, exploration in nature and the hunt for the mysterious sea worm.