Antia, the illustrious princess of the twin realms, Kamalant and Komilant, finds herself startled by the unexpected arrival of a guest at her uncle's regal abode. Lady Sofi, on behalf of her husband Chief Hamrab, extends an invitation to Antia, beckoning her to explore their isolated desert haven, the island of Roshan.

Despite Antia's reluctance to embark on this journey and her aversion to the looming arranged marriage her aunt the Queen has orchestrated with the Chief's son, her wise tutor Eskoril convinces her to take the voyage. He encourages her to document every experience and observation in Roshan through letters to him.

The ship's pace is sluggish as it sails through the seas, and the scorching sun leaves Antia's nurse, Nan, in despair. Upon arrival at the modest town of Lohat in Roshan, Antia is taken aback by the simplicity of Chief Hamrab's residence and their lodgings. The earnest and devout people of Roshan, along with their Chief, baffle her. Antia resolutely avoids Jodril, the Chief's son, yet he forms an unexpected camaraderie with her nurse. Meanwhile, Lady Sofi graciously introduces Antia to the charms of Lohat, guiding her through the bustling market and even rescuing her from a runaway beast.

Eskoril's responses to Antia's letters are terse, pressing her for details about the broader landscape of Roshan. Puzzled, she requests Chief Hamrab's assistance in joining a caravan to explore the vast desert. Jodril is appointed as her guide for the expedition.

As Antia ventures through the boundless desert, the striking beauty of a secluded oasis stirs something within her, though she hesitates to acknowledge it. A fierce sandstorm engulfs her, and she regains consciousness in a village nestled beside the Great Dune. In her hazy recollection, she vividly remembers someone gently bathing her with cool water, and a mystical pool where the water appeared to blaze. Jodril, relieved to find her safe, proposes friendship; however, tensions rise when he secretly reads her diary and destroys vivid descriptions of her dreams.

In frustration, Antia ascends the towering Great Dune, where she encounters the enigmatic Sandwriter, an ancient sage.

Despite the soul-searching moments spent amid the desert's vastness and atop the Dune, Antia pens her journey to Eskoril.

His reply, filled with alarming undertones, drives her to confide in Jodril. Together, they consult Chief Hamrab, who advises them to seek the wisdom of the Sandwriter.

Returning to the Great Dune with the caravan, Sandwriter heeds their tale and reveals Roshan's hidden core, instructing them to await further guidance. Unbeknownst to them, Eskoril has clandestinely joined the caravan. He coerces Antia into revealing the secret—a concealed reservoir of water alongside a pool of petroleum—coveted for his selfish ambitions.

As Eskoril races across the desert with his discoveries, Antia alerts the Sandwriter, who conjures a formidable sandstorm. When the storm subsides, Jodril, Antia, and the village headman solemnly return Eskoril's remains for burial. Exhausted, the Sandwriter binds Antia and Jodril to each other, foreseeing a child from their union destined to come under her tutelage.