Shen Wan, the Empress Dowager of Great Zhou who rules from behind the curtain, sets out for Helan Mountain in the northwest despite her frail health and fierce opposition. She must save her daughter, Princess Changle, who has been afflicted by a strange parasite, and eradicate the Mu clan, entrenched in the southwest and coveting the nation's fortune. The Blackwater Plain at Helan Mountain was where her ill-fated affair with the rebel general Xiao Yan ended seven years ago. Now it has become a lair where the Mu clan creates monstrous “medicine men” and schemes to summon “heavenly fire” to burn away the nation's fortune.
Armed with a prophecy left by a mysterious old courtier of the previous dynasty and half of a jade token exchanged as a pledge of love, Shen Wan takes on the Mu clan's dark arts and bizarre “medicine men” in a brutal battle, with help from Xuan Weizi, a Taoist from Mount Longhu, and others. Using herself as bait, she awakens the nation-protecting divine weapon, the Zhenyue Sword. In the end, she perishes alongside the head of the Mu clan at the mouth of the heavenly fire, having exhausted her spirit and life force.
As she lies dying, Shen Wan uses her remnant soul to activate the forbidden ancient formation, “Soul-Burning Spirit-Forging.” She transfers her final spark of life and purifying power to her daughter, A Yuan, before her soul disperses completely. In doing so, she ends the Mu clan's desire to seize the imperial bloodline and reforges the Zhenyue Sword into a sentient divine weapon. The young emperor, Li Hong, rapidly matures along the path his mother paved with her life. Deep within Helan Mountain, he uncovers a secret dating back a thousand years: this place is the “Eye of the Earth's Veins,” guarded by the ancient Jumang shamanic rites, and the Mu clan are merely usurpers who have tainted it. He obtains the Map of the Realm, which holds the fate of the land, and accepts the mandate of Heaven and the heavy responsibility it brings.
After returning to the capital, Li Hong brings the Map of the Realm to his sister A Yuan, who has shut herself away from the world. In the silent Changle Palace, the siblings face together for the first time the ancient scroll that bears their mother's sacrifice, their family's fate, and the burden of a vast realm. A glimmer of light enters their frozen hearts, and a new journey, along with unseen undercurrents, quietly begins.
