Legend has it that during the Ming dynasty, an ancient deity's book held the secrets to manufacturing powerful weapons with the ability to destroy anything. Whoever possessed this book would rule the nation. It was believed that the deity entrusted the book to the royal family as a sign of their rulership. However, during the Yuan dynasty, the Mongolians invaded and chaos ensued. The book, which should have been enshrined at the Imperial Palace, went missing and resurfaced in the hands of outlaw societies, causing many to fight for it. When the Han people regained power during the Ming dynasty, the book was returned to the Imperial Palace, but the outlaws were aware of its existence and plotted to steal it. The three most notorious robbers were the Hell-fire monk, Hua Daochang the thousand-face fox, and Duan Yun in white. During the ghost festival, the robbers snuck into the Imperial Palace to steal the book and compete for the title of "the most famous robber." In the end, the Hell-fire monk succeeded in stealing the book. To catch the robbers and recover the book, the emperor formed the Imperial Guards, which included the young and inexperienced guard Yuan Xiaotang, who would become the hero of this animated tale. The emperor ordered the Guards to find the robbers and the book, thus beginning the story.