At Zhenjiang, the tale begins with the snake-demon sisters, Blanca the white snake and Verta the green snake, as they boldly confront the demon-slaying monk, Fahai. Their purpose is to rescue Blanca's husband, Xu Xian. However, after a fierce battle, the sisters are ultimately defeated. In the aftermath, Blanca loses her precious hairpin wand, and she finds herself imprisoned beneath the Leifeng Pagoda. Verta, feeling anger towards Xu Xian for his perceived weakness, blames both him for being ineffectual and Blanca for not choosing a more powerful partner. As the chaos continues, Verta loses control once again and is drawn into a portal.
Waking up disoriented, Verta finds herself stripped of her demonic powers in a bleak modern city called Asuraville, a place renowned for housing creatures from various eras. Here, she encounters a woman named Sun, who kindly assists her in navigating this new world, along with a mysterious masked man, who unfortunately suffers from amnesia but heroically rescues them from danger. The primary threat in Asuraville is the formidable army of Ox-Heads & Horse-Faces, led by the ambitious Ox Leader, who harbors plans to dominate the city. Tragically, Sun meets her demise at the hands of the Ox's soldiers; however, Verta is fortunate enough to be saved by the Raksha army, commanded by a man named Simon, with whom she finds herself enamored.
Simon brings Verta to the All-Good Market to meet its owner, a cunning fox-demon. During her time there, she unexpectedly encounters the masked man once more. The fox-demon reveals a crucial truth: all the inhabitants of Asuraville are sent there due to an obsession. To escape, they must relinquish their tokens and leap into the Pool of Release, but this option comes with a hefty price—it robs them of their memories and will. Verta, not willing to forget Blanca, decides against entering the Pool, while the masked man struggles to recall his own obsession. Graciously, she allows him to accompany her as a token of her appreciation for saving her life.
As the atmosphere darkens, tragedy strikes again when the Ox's army brutally wipes out Simon's troops. In a desperate bid to escape some malevolent spirits, the masked man becomes compromised, and although Verta attempts to rescue him, Simon views them as weaknesses in their struggle and abandons them. Despite this setback, they manage to survive. Verta comes to understand a profound lesson: in matters of the heart, true strength is not merely physical, but lies in one’s character. She starts accepting that her sister's observations were spot on. When the masked man removes his mask, revealing a familiar face that resembles Blanca, it dawns on Verta that he may indeed be a reincarnation of her sister from a bygone era.
Returning to the market, they find Simon waiting for them as they seek guidance from the fox-demon for an alternative exit. She tells them of the Wish Bridge, a more challenging path but without the emotional toll of losing memories. Yet, before they can pursue this hope, the Ox's army descends upon the market. In a moment of redemption, Simon apologizes to Verta and engages the enemy. He lands a blow that should have been fatal, only to discover that the Ox is safeguarded by an impenetrable barrier placed on him by Fahai, leading to Simon's demise.
Following this heartbreak, it is revealed that the masked man's identity was a ruse designed by the Ox, further complicating Verta's journey. In light of these revelations, she resolves to stop depending on others and to empower herself instead. As the stakes rise, they find themselves on a bus toward the Wish Bridge, facing the perilous Black Wind Tunnel first. Here, Verta battles Fahai for what feels like an eternity, ultimately defeating him and destroying the Pagoda, thereby ensuring Blanca’s liberation in the human realm.
Time presses on as Verta races against the invading Ox, who is now vulnerable without Fahai’s protection. As the conflict peaks, the masked man sacrifices himself, transforming into an evil spirit to enable Verta's escape by carrying her to safety, leaving her with nothing but his bone flute.
One thousand years pass in the human realm, and Verta remains in search of Blanca. She stumbles upon the rebuilt Pagoda and its treasures displayed in an exhibition. Among the items, she discovers fragments of Blanca's hairpin, with one missing piece. In a moment of realization, she gathers the pieces, reconstructs the hairpin, and incorporates the bone flute, returning it to its original state. It strikes Verta, in her sorrow, that the masked man was indeed a reincarnation of Blanca, and she stirs with joy when she hears a tender voice call her name. Blinking back tears, Verta is elated to see her sister once more.
In a mid-credits scene, the fox-demon has an encounter with a river monster beneath the same bridge, presenting her with a severed fox tail. She ominously remarks that her adversary draws near and proposes a scheme for her revenge.
