In nineteenth-century China, Jungle Village is embroiled in conflicts among various clans. The skilled village blacksmith, driven by love, devises deadly weapons for these clans with the hope of using his earnings to buy the freedom of his beloved, Lady Silk, so they can escape together. Meanwhile, the local governor assigns the formidable leader of the Lion Clan, Gold Lion, the responsibility of securing a substantial shipment of gold traveling through the village. However, treachery lurks as his lieutenants, Silver Lion and Bronze Lion, conspire to betray him, aiming to snatch the gold for themselves. Their cunning plan unfolds amidst a brawl with the Hyena Clan, permitting their accomplice, Poison Dagger, the governor’s aide, to assassinate Gold. In the wake of this betrayal, Silver ascends to power as the new leader of the Lions.
Upon learning of his father’s demise, Gold's son, Zen-Yi, embarks on a quest for vengeance against those responsible. In the thick of the chaos, an undercover emissary from the Emperor, Jack Knife, enters the fray, taking refuge in the Pink Blossom, a brothel overseen by Madam Blossom, who, interestingly, also manages Lady Silk. Silver's henchmen from the Rodent Clan are dispatched to eliminate Zen-Yi before he can reach the village, but Zen-Yi proves his mettle by eliminating them in a fierce confrontation.
As the narrative unfolds, the imposing mercenary, Brass Body, is introduced and collaborates with Silver, tasked with the mission to eradicate Zen-Yi. The blacksmith, intending to secure Lady Silk's freedom, visits her at the brothel to deliver the necessary final payment. Yet, upon arriving at the village, Zen-Yi and his allies encounter Brass, who possesses a unique prowess—his skin transforms to a metallic shield upon impact, making him nearly indestructible. Despite the odds, Zen-Yi's courage is exemplified when his last remaining ally sacrifices himself, allowing Zen-Yi to evade Brass's assault.
As events swirl, the anticipated gold shipment arrives, coupled with the presence of two talented warriors known as the Geminis. Tensions peak when the Lions confront the Geminis, leading to chaos and the cunning assassination of the Geminis using mercury-tipped weapons, orchestrated by Poison Dagger. Jack, investigating these bizarre occurrences, is led to the blacksmith, a man shrouded in mystery. The Lions’ audacious theft prompts the governor to unleash his Jackal troops, determined to reclaim the gold or annihilate the village in the process.
In the heat of battle, Zen-Yi implores the blacksmith to forge him armor equipped with weapons. The Lions, suspecting the blacksmith's allegiance to Zen-Yi, resort to torture to extract information. Despite enduring unimaginable pain, including the severing of his forearms by Brass, the blacksmith remains resolute. During his recovery, he reveals his backstory as an emancipated slave from America, who adopted the philosophy and skills of monks in China to harness his inner energy for extraordinary feats.
The alliance between Zen-Yi, Jack, and the blacksmith strengthens as they navigate treachery and confrontation. Meanwhile, Madam Blossom devises a plan to conceal the stolen gold, tucked away in a crypt beneath her brothel, in exchange for a sizeable payment. On the night of the ruse, armed with concealed weaponry, Blossom's girls execute a plan to poison the Lions, transforming into a fierce faction known as the Black Widows. However, the struggle intensifies as Silk attempts to poison Brass, who ultimately overpowers her, leaving her on the brink of death.
The climactic showdown features Zen-Yi, Jack, and the blacksmith uniting with the Black Widows to vanquish the remaining Lions. A fierce battle leads Zen-Yi and Silver to the crypt where a final clash ensues, resulting in Silver’s crushing defeat alongside his stolen gold being liberated. In a poignant turn of events, the blacksmith confronts Brass, wielding his newly crafted iron forearms that shatter Brass's invulnerable façade. As the dust settles, Jack manages to thwart the Jackal troops from wreaking havoc on the village.
In the epilogue, Jack departs from the village, leaving with the gold, while Zen-Yi embraces his newfound brotherhood with the blacksmith. With their foes vanquished and peace restored, the blacksmith vows to protect the village, symbolically dismantling the weapon shop sign. Yet, in a twist of fate during the credits, Zen-Yi's pregnant fiancée is abducted by a bird clan, igniting a new quest for the blacksmith’s aid.
