Perched on the eaves of the ancient capital's old library for years, five ridge beasts fall into the city after a failed battle. Nine-year-old Xu Feifei unexpectedly becomes the new master of these five ridge beasts, forming the Rufu Guard. Feifei and the Rufu Guard embark on a journey to unravel the mysterious mission of Rufu while tackling all sorts of bizarre little problems in the city and community around them. Wherever there is a need, Rufu appears—at school, in the neighborhood, across the city—dedicating themselves wholeheartedly to becoming protectors of a harmonious community. Each time, the creative actions of the Rufu Guard will open the hearts of Feifei and her classmates, bringing them fascinating and magical histories of the ancient capital, along with the courage and joy of staying true to their初心.