There is a practical joke war going on in Stoneybrook due to a slapstick comedy festival at the Stoneybrook Public Library. Claudia gets caught up in it the worst when she sits for Betsy Sobak and breaks her leg as the result of a joke. Now the club has to convince Betsy that jokes that hurt people are not jokes at all.
Since Claudia broke her leg, she has a lot of time to sit and reflect on her life in baby-sitting. She starts to wonder if maybe she should just quit the BSC and focus on her art, like she had contemplated doing in book #12 . In the end, she realizes she would miss the kids too much and stays in the club.
Claudia's not worried when she hears her newest baby-sitting charge, Betsy Sobak, is a great practical joker. After all, how much harm can one little girl do?
Plenty. Claudia breaks her leg as a result of one of Betsy's mean jokes... and now she's talking about quitting the club. "Baby-sitting," she says, "is just too dangerous." Kristy thinks Betsy needs to be taught a lesson. She also thinks the Baby-sitters are just the ones to do it.
In Claudia and the Bad Joke, trouble starts when Betsy Sobak is carried away by the practical jokes she receives from McBuzz’s Mail Order. When I was young, I loved to order things through the mail — from the backs of cereal boxes, from comic books, and, best of all, from bubblegum wrappers. My prize possession was a piece of fool’s gold, which came in a little gray flannel sack. It cost twenty-five cents, but I thought it was very valuable. Back then, hardly any catalogues came in the mail.
But every fall, Sears Roebuck sent out its Christmas catalogue, The Wish Book. I pored through it, turning down the corners of pages on which I saw toys I wanted. Today, I still do most of my shopping through catalogues. I just love getting things in the mail, although it’s been a long time since I ordered a practical joke.