Dai Zong and Li Kui are sent to fetch the magician Gongsun Sheng from his home in Jizhou (薊州; present-day Ji County, Tianjin) as Liangshan could not counter the sorcery of Gao Lian, the prefect of Gaotangzhou (高唐州; present-day Gaotang County), in their military attack on the city to rescue Chai Jin. Gongsun has been away for a long time to visit his mother.