I hadn't heard of this story before, but it came with Secret Window, Secret Garden and therefore I just had to read this one as well.
I won't say what's happening, because the confusion that especially plays a very important role in the first part of the book is the best part. Believe me when I say it's confusing, but interesting nevertheless.
It was an enjoyable read, but I wasn't blown away by it. There are some creepy moments, but I thought the ending wasn't really satisfying.