Jill's excited about entering her basset hound, Fletcher, in the big dog show, so she and her best friend, Gwen, go to the library to learn about training dogs.But they're puzzled and surprised to find that many pictures are cut out of the special dog books they've borrowed. Who would want to destroy library books? Luckily there's strange clue on one page and that's enough to get super sleuths started on their search.The books are due back soon and Jill and Gwen don't want to be blamed for ruining them. But someone is to blame. Will they find the person in time?