In the bustling city of Donghai, residents are facing a severe water shortage that threatens their daily lives. Amidst this crisis, Nicole Fong stars as Dr. Su Junzhu, a compassionate woman working at a hospital and involved with underground activities to help the city's impoverished population. At the same time, Yunxiang, whose full name is Li Yunxiang, is an underground motorbike racer who secretly acts as a water smuggler, intentionally causing breaches in water treatment facilities to provide much-needed water to his community. Despite his illegal activities, Yunxiang genuinely cares for his fellow residents and shows a rebellious spirit against the oppressive water monopoly.
One fateful night, Yunxiang's life takes a dramatic turn when he's chased by Ao Bing, the son of Ao Guang, the powerful and ruthless leader of the De Clan, which rules the city with an iron grip. Ao Bing, portrayed by He Zhang, arrogantly pursues Yunxiang and his sister Kasha, played by Victoria Grace, to reclaim his stolen bike. During the chase, Yunxiang and Kasha are wounded, and Yunxiang’s anger ignites a mysterious, fiery power that sets Ao Bing’s arm ablaze, forcing the siblings to escape.
Yunxiang wakes up in a hospital, where he finds that his wounds have mysteriously healed overnight, yet tragically, Kasha has lost her right leg. He soon discovers that the woman he met during his races — Dr. Su Junzhu — works there. When Ao Guang, the city’s formidable ruler, appears to personally apologize for his son’s reckless actions, offering Yunxiang back his bike and a hefty sum of money, Yunxiang, embittered, refuses the offer. Recognizing Yunxiang’s extraordinary powers, Ao Guang’s forces are ordered to eliminate him. In a fierce confrontation, they run Yunxiang’s brother Jinxuang, played by Harrison Xu, off the road. Yunxiang fights back fiercely, using his emerging supernatural abilities to defeat the assassins.
During this turbulent period, Yunxiang is rescued by a mysterious masked figure who reveals himself to be the reincarnation of Nezha, a legendary warrior spirit. Confused but intrigued, Yunxiang chooses to leave rather than join the masked man, who is later identified as the Six-Eared Macaque, a powerful mystical being played by Jason Ko. Ao Guang, furious about Yunxiang’s abilities, discusses a secret plan with his son Ao Bing to eliminate him. He also offers a substantial reward to the Macaque to kill Yunxiang, but the masked warrior refuses the deal.
Meanwhile, Yunxiang begins training to control his newfound powers, with help from the Macaque, who demands a motorcycle as part of his training. As Yunxiang learns to harness his abilities, he crafts special armor to regulate his fiery flames and even creates a prosthetic limb for Kasha. During one of his training sessions, Yunxiang uncovers the Macaque’s true identity and learns about the presence of Nezha’s primordial spirit within him, which gives him immense, though unstable, power.
His efforts are disrupted when Liang, a jealous former coworker, is manipulated by Ao Guang to sabotage Yunxiang. Liang kills Yunxiang’s trusted ally Six and targets Kasha, forcing her to escape before the hospital is bombed by De Clan assassins. Yunxiang confronts and defeats several enemies but is eventually attacked by Rosy Cloud, a one-armed warrioress played by Xiaoming Xuan, who is seeking revenge because of her own past losses. During the chaos, Yunxiang’s father is wounded and dies, leaving Yunxiang devastated and angry. He then marches to the De Clan’s stronghold to face Ao Guang directly.
At the De Clan estate, Yunxiang resumes his fight against Ao Guang’s forces, finally clashing with Ao Bing, who transforms into a fearsome dragon. Despite the overwhelming odds, Yunxiang defeats Ao Bing by tearing off his metallic spine, showcasing his mastery over his powers. Throughout this fight, the Macaque intervenes to restrain Rosy Cloud, revealing her connection as a disciple of the demoness Shiji, and she confesses her desire for revenge against Nezha, who killed her friend for sport.
Yunxiang uncovers the tragic past of Nezha, who was forced into a desperate act of rebellion after killing Ao Bing's previous incarnation. The story reveals that after Nezha killed his predecessor, the Dragon King of the East Sea demanded an apology — which Nezha refused, choosing instead to end his own life. Disillusioned, Yunxiang is left contemplating the complex history of his legendary predecessor.
The Macaque, who ultimately reveals his true identity as Sun Wukong, informs Yunxiang that Ao Guang’s undersea palace holds a vital secret — the water of the entire city, controlled by river dragons kept in restraints. The palace is also the site where Ao Guang is manufacturing a powerful artifact called the Dragon Pearl, necessary for his dark plans. Determined to save his city, Yunxiang gathers his courage and infiltrates the palace, where he witnesses Ao Guang kidnapping Su Junzhu to distract him.
In the ensuing battle, Yunxiang confronts Ao Guang in his dragon form, managing to kill Rosy Cloud and finally defeat Ao Guang, who swallows the Dragon Pearl in a desperate attempt to summon a massive tsunami by unleashing the river dragons. Yunxiang tries to halt the catastrophe using a special item known as the Sky Ribbon, but it shatters, allowing the dragons to escape and the tsunami to threaten Donghai.
In a dramatic final act, Yunxiang harnesses Nezha’s primordial spirit to kill Ao Guang, sacrificing his own life in the process. As he dies, he pleads with Nezha to save the city. The primordial spirit resurrects him and, together, they use the Sky Ribbon to redirect the angry dragons, saving Donghai from destruction.
In the aftermath, Yunxiang accepts his role as a hero and protector of the city he loves. With the help and inspiration of Dr. Su Junzhu and Kasha, he finds peace and a renewed sense of purpose, concluding his journey from a rebellious smuggler to a legendary figure destined to defend his people against cosmic forces and ancient demons alike.
