The Sign in the Smoke: Nancy Drew Diaries, Book 12

Dear Diary,

When Bess asked George and me to be counselors at her old camp, I thought I was in for a relaxing week.
 But trouble always finds me. I heard about a camper who had drowned in the lake years ago and dismissed it as a ghost story. But then something pulled me under during a swim lesson. And then our cabin's sleeping bags disappeared!
 You would think after solving so many cases involving ghosts, I wouldn't believe in them. But these scary events are making it hard not to. All I know is that I have to make sure my campers are safe at Camp Cedarbark.