When Dennis breaks his skateboard again, Dad agrees to buy Dennis the best skateboard there is as a replacement if he is able to win a prize at the upcoming school award ceremony. At this late stage, the only prize that Dennis has a chance of winning is the best behaviour prize, so he does everything he can to win the contest. When Walter is ruled out for knocking over the guest speaker, Dennis looks certain to win—until Gnasher escapes from the house and follows Dennis to school, where there is a reception full of food. After chaos ensues, there seemed no chance of winning the best behaviour prize but Mr Guff finds the day's events so funny that he awards Dennis a special prize for outstanding individual achievement. Dennis gets his prize and earns his new skateboard.