During the middle of the Ming Dynasty, the eunuchs were in power. Zhou Huai'an, the former head of the forbidden army, was dissatisfied with the eunuch Cao Shaoqin's use of the "East Chamber" as a secret service, so he indignantly resigned from his post and disappeared into the jungle, where he joined hands with the loyalists to deal with the East Chamber. Cao regarded Zhou as a great danger, so he framed Zhou's former superior Yang Shangshu of the Ministry of War, and took Yang's orphan to Dragon Gate as bait to lure Zhou to appear. Zhou and his lover Qiu Mo Yan, together with a group of green men, plan to rescue the orphan and escape from the country. They stayed at the Dragon Gate Inn and were followed by the army of the East Chamber. Both armies fought a duel to the death at the Dragon Gate.