As the Jingkang catastrophe approaches, death row prisoner Qin Ye escapes death by a hair's breadth. Using saltpeter to make ice and break free, he saves the assassinated Princess Zhao Fujii, instantly becoming an imperial son-in-law of the Song Dynasty. Facing the joint suppression of Grand Commandant Cui Yan and powerful noble families, Qin Ye unveils advanced iron-smelting, crossbow, and gunpowder technologies to vigorously strengthen the military and enrich the country. Knowing full well the tragic outcome of the Jingkang national humiliation, he vows to reverse the destiny of the Song Dynasty. When the Jin troops march south, Qin Ye leads his army to guard the Yellow River and fiercely battles at Taiyuan, using a counter-espionage scheme to crush the Jin army and forcing the Jin state to sign a peace treaty promising not to plunder the Song imperial house. Triumph and glory are followed by framing and slander, but in the moment of crisis, Zhao Fujii is willing to risk her life to protect Qin Ye.