The Rugrats and the Pickles go to a medieval fair, where Didi, Stu and Grandpa will be helping out. While Didi makes stained-glass windows, Stu and Grandpa operate a mechanical dragon that Stu invented. However, thanks to the mechanical dragon's numerous glitches, it ended up making an ""Ye Olde Mess"" out of the entire fair. However, there's one thing that can help defeat the dragon... Reptar. And its all based on the Rugrats' wishes.