The narrative picks up with the protagonist, Jandarum Alpius, waking to find the beautiful, white-haired girl, Dearm (Dia), already by his side. Dia, who calls him "brother," prepares breakfast for him and expresses her happiness in being able to help him. Jandarum, an archaeologist by aspiration but currently working as an adventurer, finds Dia's devotion unusual, sensing a profound, almost precarious emotion beneath her cheerful demeanor. Despite his lack of memory of having a sister, he feels compelled to protect her.
Jandarum's current goal is information gathering in the Ednile Kingdom, a desert nation reminiscent of ancient Egypt. He possesses memories of a past life on Earth, where he was unable to pursue his dream of archaeology due to family obligations. He died saving a child, and was reborn in this fantasy world with magic and strange creatures, determined to fulfill his archaeological ambitions.
While in the capital city of Edna, Jandarum and Dia visit the bazaar. Jandarum is interested in Ednile's myths and history, and strikes up a conversation with an elderly man about the kingdom's mythology. Dia offers a unique interpretation of the royal crest's symbolism, suggesting the god Lera consumes power rather than physical offerings. Their discussion is interrupted by the old man's playful, yet probing, questions about their sibling relationship.
Later, while exploring the desert, Jandarum and Dia observe the unique properties of the sand, which flows like water and is influenced by magic. They witness a sandship and then a conflict between sandship fishermen and a group extracting crystals from the sand. Jandarum, driven by his desire to understand the history and culture, intervenes. He learns that the crystal extractors are motivated by the high demand for sand crystals as materials for magic-powered weapons, a trade supported by the royal family and primarily with the Zinedre Empire. The fishermen, however, lament the depletion of the desert's resources and the disruption of the ecosystem.
During this encounter, they are attacked by massive sand scorpions, dubbed "Sand Sea Reversals." Dia, revealed to be an incredibly powerful, ancient golem, easily repels the creatures, demonstrating immense strength and speed. Jandarum, observing the scorpions' behavior and the crater left by their breath, deduces that they are returning the extracted sand crystals to the desert, acting as regulators of the ecosystem. He theorizes that the conflict arose from the over-extraction of sand crystals, upsetting the natural balance.
The group then visits a bustling outdoor eatery in Edna, where they meet a young woman named Myusha. Myusha claims to be searching for fish to offer to the god Lera, contradicting the established tradition of offering crystals and swords. The locals dismiss her claims, labeling her a sinner for disrespecting the royal family. Jandarum, however, senses a deeper truth and suspects Myusha might be a "shrine maiden," a rare individual who can hear divine voices. He learns that Ednile has been without shrine maidens for centuries, and that Myusha's parents died in a sandstorm after she warned them.
Myusha is revealed to be a prisoner, albeit one whose escapes are seemingly tolerated by her kind guard, Halpon. Halpon explains that Myusha's claims of the king being a "fake" and her divine pronouncements are attributed to her mental instability following her parents' death. However, Jandarum believes Myusha's claims are linked to a potential alteration in the royal lineage, possibly through infidelity during the reign of King Udals, the father of the popular "Golden King" Adalga. This theory suggests the current royal family might not be the true descendants, and if the rituals to Lera are not performed correctly, the kingdom could lose its divine favor.
Jandarum resolves to investigate further, despite the potential danger of antagonizing the royal family. He is driven by his passion for history and understanding the interconnectedness of past and present. Dia, ever supportive, pledges her full capabilities to aid him.
Later, back at their lodging, Dia prepares a unique meal for Jandarum. She reveals her ability to create new dishes by combining ingredients and experiences, and her constant work while Jandarum sleeps. Jandarum notices Dia's unusual behavior, including a stumble and a claim of fatigue, which contradicts her golem nature. He suspects she is hiding something, possibly a decline in her own power, but decides to observe her for now.
The investigation into the royal lineage continues, with Jandarum and Dia gathering information from the middle-class citizens of Edna. They learn about King Ordans, whose achievements were overshadowed by his aggressive conquests, and King Adalga, who brought prosperity through trade. However, Jandarum finds the reign of King Udals, Adalga's father, particularly suspicious due to his lack of historical recognition. He connects this to the absence of shrine maidens, suggesting a potential disruption in the royal bloodline around that time.
Their inquiries are abruptly halted when Ednile soldiers arrive to arrest Jandarum and Dia. Dia prepares to defend them, but Jandarum calms her, opting for a more measured approach. As they are led away, Jandarum notices the soldiers' fear of Dia, and reflects on the precarious balance of Myusha's situation, where her claims are dismissed as madness but her potential truth could destabilize the kingdom. He reaffirms his commitment to uncovering the truth, driven by his love for history and the belief that all events are interconnected.