A substitute teacher makes life hard for Arnold and Dudley, so they try to make things difficult for him in return. When one of their pranks leads to Arnold getting hit by accident, they go to the principal and tell him that it was done on purpose, which gets the teacher in trouble and nearly gets him fired until Arnold and Dudley come clean about what really happened.

When Kimberly submits a candid picture of Arnold with his butt exposed to a photo contest, he is infuriated and demands that Kimberly withdraw it, but the picture remains in the contest by mistake and almost ruins Arnold's chances of winning the class election.