Many urban legends surround the famous "Sulong well" near Beixinqiao in old Beijing. Old well with underground chain. According to legend, in the early Ming Dynasty, an ancient dragon was trapped in this place. After the capital was moved from Nanjing to Beijing in 1421, the dragon was inadvertently disturbed by the great momentum. This ancient dragon was ferocious and soon flooded the streets of Beijing, so Emperor Zhu ordered the retired wizard Yao Guangxiao and his four heroes of Lubang to go outside and find a dry place near a small bridge. I asked you to lock the beast in the well. 100 years later, the descendants of the four Luban Masters reunite to investigate the truth about the Suorong Well...