The blurb for book no. 6 goes like this: What is Uncle Quentin up to, all alone on Kirrin Island? He won't let anyone visit, not even George and the rest of the famous Five. But Uncle Quentin isn't really alone on the island--someone is watching his every move.
The truth is that a new resident in Kirrin and he has a son. George and her cousins' make friends with his son and this new resident has got something to do with the island.
My favourite part was when they discover the underground tunnel leading to Kirrin Island which goes under the sea. I would rate this book 6/ 10. Anyone would be able to enjoy this book.