In the early 19th century, amidst the backdrop of French-occupied Germany, two brothers, Will Grimm and Jake Grimm, have perfected their craft as traveling con artists. They utilize Jake's extensive knowledge of folklore to deceive unsuspecting villagers into hiring them to eradicate mythical creatures. Accompanying them are their loyal sidekicks, Hidlick and Bunst, who are always ready for the next adventure. Their latest scheme takes place in Karlstadt, where they cleverly pretend to "kill" a witch's ghost, leaving the village in awe of their supposedly supernatural abilities.
However, their triumph is short-lived when they are apprehended by the ruthless Italian torturer Cavaldi, who delivers them to the formidable General Delatombe. The general, intrigued by the brothers' reputation for conjuring fake monsters, mistakenly believes they are responsible for the eerie disappearances plaguing the quiet village of Marbaden. What the general doesn't realize is that a true supernatural entity is stalking the land: a stunning yet sinister 500-year-old Thuringian Queen has been abducting young girls to feed her insatiable lust for beauty.
The tale reveals that the queen's descent into darkness began with her husband, King Childeric I, who sought to build a city in the forest. Consumed by her obsession for eternal life through dark magic, the queen constructed a towering refuge from the Bubonic plague. Tragically, while her loved ones succumbed to the disease below her, she learned too late that the plague was carried by the wind, not merely physical touch. Though her spell granted her eternal life, it robbed her of her youth and beauty, making her desperate to reclaim what she had lost. Already, she has drained the blood of ten young women and seeks twelve more to complete her ghastly ritual.
Accompanied by her werewolf huntsman, who wields a magical axe, she entangles herself in an intricate web of dark enchantments, utilizing crow familiars and various forest creatures to aid in her malevolent quest. Meanwhile, the Grimm brothers, with the help of Angelika, a clever huntress from Marbaden, stumble upon the queen's ominous tower hidden deep within the woods. As fate would have it, their horse is unknowingly infested with spider eggs, leading to a horrific transformation one fateful night.
As they return to the village, they are greeted by a shocking sight: General Delatombe arrives with news of the horrific events unfolding in the forest. The following morning brings even greater chaos when the brothers discover to their horror that their horse has devoured a young girl and fled into the woods. An urgent chase ensues as Angelika and the brothers pursue the creature, joined by Delatombe, whose intervention adds a complex layer to the unfolding drama.
Reluctantly, Cavaldi returns the brothers and Angelika to Delatombe's stronghold, where he menaces the idea of executing them for their failure. However, a clever ruse by the Grimms convinces the general that the peculiar occurrences in the forest are the work of German rebels, leading him to send them on another mission while Cavaldi stays behind with Angelika in the village.
Deep in the forest, Jake, Hidlick, and Bunst toy with a catapult as they plot to breach the tower’s defenses. Yet, their plans are interrupted when Hidlick and Bunst encounter an unsuspecting girl, Sasha, leading to a calamitous series of events triggered by a fallen crow. In a desperate attempt to rescue her from the transformation into a grotesque mud creature, chaos ensues, with Sasha meeting a tragic end as the mud monster morphs into a gingerbread man and sinks into the depths of the well.
As Jake scales the tower’s roof, he stumbles upon the grim remnants of the queen's past victims, with twelve crypts laid bare. Complications arise when Sasha is resurrected in a trance-like state. It becomes evident that the magic axe is the only thing feared by the forest's trees, a fact that Delatombe exploits when he captures the brothers, accusing them of being mere charlatans. As French soldiers begin to torch the forest, tensions rise, and Cavaldi grapples with his growing sympathies for the Grimms.
In an unexpected and brutal twist, Angelika's father, who is under the Queen's curse, tragically drowns her. As the brothers hasten to the tower, the Queen conjures a fierce wind that extinguishes the forest flames. Delatombe, upon realizing the Grimms' escape, tracks them down with Cavaldi in tow, leading to a climactic confrontation.
In an act of unforeseen betrayal, Cavaldi refuses to execute the Grimms and faces a grim fate himself, leaving Delatombe vulnerable to a savage attack that ends in impalement. But as the ethereal Mirror Queen takes her final breath, a careless act by Jake shatters the mystical mirror that held the tower's enchantment. This act sets off a catastrophic chain of events as the werewolf undergoes a terrifying transformation, aided by the shards of glass.
Yet, amid this chaos, a tender kiss from Jake revives Angelika, along with the eleven other victims, and even rekindles the life of Will. With darkness vanquished and the villagers of Marbaden rejoicing at the return of their daughters, the brothers are celebrated for their bravery. In a surprising turn, Cavaldi casts aside his wicked persona and joins in the festivities. Embracing their victory, the Grimms decide to embark on a new quest to tell the enchanting tales of magic that linger just outside the realm of reality.
