'Bag of Bones' by Stephen King is a very intense novel. Mike Noonan is a second rate author, never making it higher than the top 15. When his wife, Johanna, dies suddenly and unexpectedly, he is devastated. Especially so after he finds out that she was pregnant; something they had been trying to do for years. He becomes mildly depressed. Then, he starts to hear things about her that he'd never heard; she had apparently been sneaking around and digging into other peoples' lives in the months immediately preceding her death. Four years after her death, he goes to Sara Laughs, the couple's summer cabin.
The first night he is there, he hears very strange noises at night, with no explanation. On a street near his cabin, he soon meets Kyra and Mattie Devore, who both put a twist in his already strange story.
I personally would recommend this story to a rather mature young adult, who has a high reading level. I'm 14 and I found this story a little confusing and slightly inappropriate at times, but overall, it is a well written mystery story.