In the final years of the Ming dynasty, during the Chongzhen reign, the Ministry of Works monopolized the plans for red-haired cannons brought by Portuguese missionaries. Zhao Shizhen, a firearms craftsman skilled in reverse mold casting, discovers Western military tactics hidden in the cannon barrels' inner layers. Caught between the Ming court, rebel armies, and Portuguese merchants, he tries to keep firearms technology from falling into Qing hands.
