In 12th-century England, Count Thibault Malefete from France is on the cusp of marrying Princess Rosalind, the daughter of the reigning English king. As a valiant knight, Thibault is always prepared to come to the rescue of a damsel in distress. However, during the lavish wedding banquet, an unexpected twist occurs when the villainous Earl of Warwick covertly gives Thibault a potion intended for Rosalind by a witch he hired. This potion causes Thibault to hallucinate, leading him to tragically kill his own bride, believing she has transformed into a fearsome monster.
The Earl of Warwick, himself infatuated with Rosalind, orchestrated this sinister plan to eliminate Thibault in order to claim Rosalind's substantial dowry and riches. As Thibault faces a death sentence for his actions, he implores his loyal servant, André Le Paté, to seek out a wizard who can help him reverse his catastrophic mistake. Their quest leads them to an eccentric wizard, played by Malcolm McDowell, who provides Thibault with a potion designed to send him back to the critical moment before he mistakenly killed Princess Rosalind. The wizard, metaphorically likening time to "a mountain riddled with tunnels," promises to open a passage for Thibault to amend his error.
However, a mishap occurs, and instead of returning to the 12th century, Thibault and André find themselves in the 21st century, awakening in a Chicago museum that was once Thibault's castle. Their arrival causes pandemonium, resulting in their arrest as they grapple with the modern world, mistakenly identifying cars as red dragons and wreaking havoc in their wake. They are ultimately saved by Julia Malefete, a museum employee who bears a striking resemblance to Rosalind. Intrigued by Thibault’s family crest, which mirrors her own, Julia begins to think of Thibault as a long-lost cousin presumed dead in a yachting accident.
As their relationship unfolds, she learns that Thibault is actually descended from her family and realizes his imperative to return to the 12th century to rectify the past. Before embarking on their journey back in time, Thibault takes a stand to protect Julia from her greedy fiancé, Hunter, who is complicit in selling Julia’s ancestral estate under dubious pretenses. As Hunter’s true motivations surface, Thibault and André must navigate contemporary society's norms, showcasing their naiveté towards modern conveniences like electricity, plumbing, and telephones.
Amid humorous escapades at a trendy restaurant, where they struggle with table manners, the duo also finds moments of romance. André is enchanted by a gardener named Angelique, who introduces him to the liberating notion of equality. As the wizard continues to realize his error, he travels into the future to correct the botched spell, ultimately preparing a successful potion to facilitate Thibault’s return to his rightful time. Julia, on the other hand, confronts Hunter about his duplicitous plans and resolves to reclaim her heritage.
In a climactic twist, as Thibault returns just before the fateful incident with Rosalind, he seizes the opportunity to change his fate and safeguard his love. The Earl’s desperate attempt to avoid the poisoned wine results in his unintended demise. The narrative concludes with a happy reunion for Thibault and Rosalind in the past, while in the present, Julia embraces her destiny, meeting a man who possesses deep knowledge of her family tree. Meanwhile, André and Angelique set off on their own adventure, humorously navigating their newfound relationship with a thrilling ride toward Las Vegas.
