Two hundred years after the Norman Conquest, during the reign of King Edward I, the story begins with a Saxon scholar named Walter of Gurnie, played by [Orson Welles], who is the illegitimate son of the recently deceased Earl of Lessford. Upon returning from Oxford, Walter listens to the reading of his father's will, and although he receives only a modest gift of a pair of boots, he instinctively recognizes it as a symbol of his father's love and affection. This moment marks a poignant reminder of the complicated relationship between Saxons and Normans during this period of English history.
The earl's Norman widow, mindful of potential unrest, takes Saxon hostages—an act that sets off a series of daring events. Walter, moved by a sense of loyalty and justice, joins a group of Saxons who successfully free the hostages but, in the process, attracts too much attention and is forced to flee England to avoid repercussions. Alongside his loyal friend, Tristram Griffen, a skilled Saxon archer and fellow adventurer, Walter embarks on a remarkable journey filled with danger and discovery.
Their quest leads them to Cathay, an ancient and mystical land in China, which at this time is under the influence of the Mongol Empire during the Pax Mongolica—an era of relative peace and stability across Eurasia. They join a caravan laden with gifts from a merchant named Anthemus to Kublai Khan, the powerful Mongol ruler preparing for an invasion of the Chinese territories. The caravan is under the protection of the formidable Mongol general Bayan, known as the Hundred Eyes, a figure who commands both fear and respect. Bayan becomes intrigued by Walter’s scholarly knowledge and Tristram’s exceptional skill with the English longbow, which impresses the Mongol leader.
The caravan's journey is complicated by the presence of Lu Chung, the caravan's leader, who is also the head of the expedition. Lu Chung begins to blackmail Walter into helping him secretly free Maryam, known as the "Black Rose," who is the half-English sister of Anthemus. Maryam, portrayed by Cécile Aubry, secretly harbors feelings for Walter, but he remains distracted by his adventurous pursuits. She is being sent as one of the royal gifts from China, and her love for Walter adds emotional depth to the unfolding story. Meanwhile, Tristram grows increasingly uncomfortable with the violence and bloodshed surrounding their travels and decides it's better to escape. He takes Maryam with him, wishing to see her safely in England.
Bayan, ever the strategic figure, sends Walter on an important diplomatic mission to meet with the Empress of the Song dynasty—a Chinese ruler steadfastly resisting Mongol control in the northern regions. Upon arriving, Walter is told he must remain in Cathay as a guest indefinitely, a twist that traps him in a strange land far from home. During this stay, he learns that Tristram and Maryam have been captured and imprisoned, heightening the stakes. Amid rising tensions, Walter realizes that he has developed genuine feelings for Maryam. The trio's attempted escape ends tragically when Tristram dies in the effort, and Maryam, waiting in a small boat for Walter, drifts away before he can reach her. Devastated, Walter returns alone to England.
Back in England, Walter is greeted with honor by King Edward I, who recognizes the invaluable cultural and scientific knowledge, including the revolutionary concept of gunpowder, that Walter has brought back from China. Walter is knighted and granted a coat of arms, solidifying his status as a man of great importance and learning. The story concludes with the arrival of two Mongol emissaries from Bayan, who have brought Maryam, the Black Rose, now to join Walter in England—a symbol of the distant yet interconnected worlds they have traversed.
This epic tale, rooted in themes of loyalty, love, adventure, and cultural exchange, showcases the extraordinary journey of a Saxon scholar navigating a world on the brink of monumental change, ultimately bridging East and West through courage and knowledge.