Song Jiang sanctions the plan devised by Tang Long to recruit Xu Ning. Shi Qian, who could scale walls and move on rooftops to get into premises, sneaks into Xu's house after nightfall to steal a precious family heirloom of his - an impenetrable lightweight golden armoured vest. Tang Long then pretends to call on Xu the next morning. Upset with the loss of the vest, Xu believes Tang's claim that he has just seen a man carrying a box like the one containing his prized heirloom. So Xu embarks on a long chase after Shi Qian, accompanied by Tang Long, which takes him to the vicinity of Liangshan. He is then drugged and taken to the stronghold. When he comes to, he has no choice but to join Liangshan.