This is a level 2 early reader (AR test at level 2.9, .5 points) with chapters for those emergent readers.  I generally like the Cam Jansen mysteries but didn’t care for this story due to characterization issues.  A main character, Cam’s aunt, although an adult in the story, behaved more like a disruptive young child.  Her behavior didn’t make sense to me and probably would be distracting to young readers as well.  The story is about figuring out what happened to Cam’s box of popcorn which went missing during the circus.  The mystery is properly resolved and I did enjoy the memory game included in the back of the book.