The story begins with a young girl, alone and hungry in a messy home, counting her last snack. Her mother returns, heavily made-up but distraught. The mother, blaming the girl for her failed marriage, drags her to the bathroom and attempts to drown her. At this moment, the bathroom distorts and flashes with white light.
The scene shifts to a celestial space where a Goddess observes a large crystal ball showing the girl. A male attendant appears, and the Goddess explains she was reviewing the memories of a soul she had stored for reincarnation. She had saved the girl and her mother due to their tragic fate, though it resulted in both becoming souls. The attendant inquires about their destination, "Nean Star," and the Goddess reveals they have found a connection to the "Soul Fragment Path," a singular, unknown path connecting the universe, which might help locate the star. She decides to reincarnate the girl and another soul, "Fian," to Nean Star, acknowledging their current imperfections but stating they are the only souls left.
Meanwhile, a dark, armored figure emerges from black mist, revealing Nean Star on a display. He vows to reclaim his body from Fian and Nevia and summons countless "Shadow" monsters, declaring his intent to prevent the Goddess from interfering. He then disappears with his shadows.
On Nean Star, in a forest, Nean awakens. He is revealed to be the legendary former hero who saved the world from the Demon Lord Kage. The narrative then introduces the world of Nean Star, where two elf girls, Fian and Nevia, were born and eventually awakened as celestial beings, defeating the Demon Lord Kage.
In a peaceful village, a village elder tells children the story of Fian and Nevia. Nean, disguised as a traveler, overhears this and reflects on the world's peace. He learns about "Magic Gear," including Spell Cards, Spell Card Holders, Spell Bangles, and Spell Shields, which utilize advanced technology derived from ancient magic. He witnesses a demonstration of a Spell Card activating a fire spell and a Spell Shield nullifying it.
Nean then discovers a hidden cave with a mechanical door, which he opens using a device called "Debussy." Inside, he finds a laboratory and a coffin-like box. Upon opening it, he discovers two young girls, elves, asleep. One, Tsumugi, awakens and, along with the other, Sanae, reveals they are from Earth and were killed by Tsumugi's mother. Nean explains they cannot return to Earth and offers them refuge. He demonstrates his magic, impressing the girls.
Over the next month, Tsumugi and Sanae adjust to their new lives. They learn the world's language, "Bio-Language," and begin training in magic under Nean. Nean reveals his own complex nature as an "Awakened Celestial" and his past as Fian and Nevia, who merged to become him. He explains the world's magic system, including "Magic Power" and "Fighting Spirit," and the existence of different races.
Nean decides he must embark on a journey to fulfill a mission, leaving the girls behind temporarily. They insist on accompanying him, and Nean agrees to teach them magic. They travel to a village and learn about the world's currency and the dangers of "Outsiders," alien beings that attack living creatures. They also discover that the "Soul Fragment Path" is used for the train's power.
Nean takes on a job to draw magic circles onto blank Spell Cards to earn money for their journey. He also learns about "New Magic," which bypasses Spell Shields, and the existence of "Triggers," firearms that utilize Spell Cards.
They board a train to the commercial city, where they encounter various races and witness the prevalence of firearms. They arrive at the Guild, a grand building where Nean plans to find work and acquire Magic Gear. They learn about the world's structure, with a central dungeon where Shadows appear, and the importance of Soul Fragments.
Nean decides to enroll the girls in an academy to learn New Magic, as his own powers are limited to Ancient Magic. He plans to stay near the academy while continuing his mission. Upon reaching the commercial city, they encounter an Outsider, a powerful white-armored being. Nean defeats it with his unique magic and sword skills, but realizes the Outsider's strength and the limitations of his own abilities against New Magic. He also learns that Outsiders are alien invaders.
The story concludes with Nean, Sanae, and Tsumugi on the train, discussing the world's shape and the existence of an academy. Nean reveals his past as a salaryman who died of overwork and was reincarnated, living for centuries. He proposes a plan for them to attend the academy while he continues his travels, assuring them he will return. They arrive at the commercial city, a bustling metropolis filled with various races and advanced technology, and head towards the Guild.
