At the Suspended Sword Bridge in Guankou, Shu, guarding the river mouth to prevent evil flood dragons from emerging, the young Erlang Shen, ostracized by villagers due to his unusual third eye, embarks on a path of cultivation after accidentally injuring a bridge guard. The black flood dragon deceives his sister Ahua into destroying the bridge, causing a great flood. Ultimately, Erlang Shen returns from his training, defeats the flood dragon clan, and protects Guankou.