I have a book containing two Mystery and two Adventure stories.One of it is Mischief at St.Rollo's. The others are Smuggler Ben, The Children of Kiddilin and The Secret of Cliff castle.
I tried browsing through the cave of books looking for more stories under Mischief at St.Rollo's. But the cave of books didn't have anything of that sort. I searched for The children of Kiddilin too, but couldn't find it either.
I wonder whether it is hidden among the jutting rocks in the cave.