Camp of No Return — J.H. Reynolds

In the fourth Monsterstreet book, the best summer of Harper's life could be her last...

On the way to Camp Moon Lake, the most magical summer camp on earth, all Harper can think about is her parents' looming divorce. Soon enough, though, the outdoor movie theater, the water park, and the chocolate buffet begin to work their magic on her.

But then campers start to disappear, and Harper notices the counselors acting unusual. The cheerful facade of the camp falls apart to reveal strange secrets and a sinister plan. Escaping will take everything Harper has -- maybe even her life.