During the siege of Nan Commandery, Zhou Yu ordered Gan Ning to lead a detachment to take control of Yiling (夷陵; present-day Yichang, Hubei), but Gan Ning came under attack by a separate enemy force led by Cao Ren's subordinates. When Gan Ning sent a messenger to Zhou Yu's camp to request for relief forces, most of Sun Quan's officers saw that they did not have enough men to spare, so they refused to help Gan Ning. Lü Meng, however, insisted on saving Gan Ning. He told Zhou Yu and Cheng Pu: "I suggest we leave Ling Tong behind while I follow you to help Gan Ning. It is imperative that we lift the siege (on Gan Ning) because he may not be able to hold out for long. I assure you that Ling Tong can defend our current position for at least ten days."