The story begins in the world of Inglens, a land where magic flourishes and various races coexist. As spring arrives, cherry blossom petals drift on the wind, eventually reaching the village of Avalon. Here, a red-haired girl named Elice, who is about to turn twelve, is introduced. She lives with her adoptive parents, Yurris, a strawberry farmer, and Elishia, a homemaker. Elice's companions include Kuro, Elishia's black cat Nightmare, and George, Yurris's red bull Nightmare.
The chapters detail Elice's life in Avalon, her close relationship with her parents, and the simple joys of village life, like enjoying her father's strawberries. A significant aspect of this world is the concept of Nightmares, familiars that young people manifest around their twelfth birthday, often taking the form of animals or even inanimate objects. Elice eagerly anticipates the arrival of her own Nightmare, wondering what form it will take.
A turning point occurs one night when Elice, unable to sleep, ventures into the strawberry fields. She encounters a thief and, pursuing them into the forest, finds herself surrounded by dangerous creatures called Ketshies. Just as she is about to be attacked, a boy in shining armor appears, wielding a sword that glows with light. He single-handedly defeats the Ketshies and introduces himself as Arthur, a knight sworn to protect her. Arthur, who possesses the ability to change his appearance and summon a white dog named Kavas, is revealed to be the legendary Knight King Arthur, the first and most powerful Nightmare.
Arthur's sudden appearance and his connection to Elice cause a stir. Yurris, Elice's father, is particularly distrustful of Arthur, despite his protective actions. The family is then visited by Heinrich, a teacher from the prestigious Graceville Magic Academy, and Adolf, the Academy's headmaster. They reveal that Arthur is the original Nightmare and that Elice, as his chosen master, is in potential danger. To ensure their safety and to understand Arthur's nature, they propose that Elice and Arthur enroll in the Graceville Magic Academy.
Elice, though initially overwhelmed, agrees to the proposal, seeing it as an opportunity to learn more about Arthur and her own destiny. Her parents, while concerned, support her decision, with the kingdom offering to cover all expenses. Elice and Arthur, accompanied by Kavas, embark on a journey to Graceville, a magnificent island kingdom. They travel by ship, where Elice experiences the vastness of the sea and Arthur remains stoic.
Upon arriving at Graceville, they are met by the dorm supervisors, Alex and Bianca, and their Nightmares, Blot and Blanca. Elice and Arthur are assigned to live together in a separate house between the boys' and girls' dormitories, a unique arrangement due to their master-Nightmare bond. The chapters culminate with Elice and Arthur attending the entrance ceremony for the Graceville Magic Academy, where the energetic Headmaster Adolf delivers an inspiring speech, setting the stage for their new lives as students and hinting at the challenges and discoveries that lie ahead. The narrative also briefly introduces other characters and their Nightmares across different regions, suggesting a wider world and interconnected destinies.
