The story begins with the engagement of Princess Isabella of Toulouse to Crown Prince Brad Montfort of the Kingdom of Monfort. At the academy's graduation party, Brad publicly breaks off the engagement, accusing Isabella of mistreating Lily Bennett, a baron's daughter who is destined to become a saint. Brad declares his love for Lily and announces their engagement. Isabella, a woman of silver hair and purple eyes, remains stoic, accepting her fate. Brad, angered by her lack of reaction, has the sons of the Prime Minister, Knight Commander, and Magic Commander, who are his close aides, present accusations against Isabella. Isabella admits to orchestrating these actions, acknowledging her delayed response as a strategic error. Brad then strips Isabella of her noble status and banishes her to a convent in the north.
Forced into a plain carriage, Isabella is taken north. Her family, the Duke and his son, are away on diplomatic missions, leaving her unprotected. She realizes Brad timed this perfectly, knowing she would have no support. Isabella reflects on her ten years of service to the kingdom and Brad, noting his infatuation with Lily and her failed attempts to dissuunt him. She understands that Brad's position as Crown Prince relies heavily on the support of the Toulouse Duchy, as his grandfather, the former king, had many illegitimate children, leading to past succession disputes. The current king secured Brad's position by arranging his engagement to Isabella. Isabella foresees political turmoil and civil war due to this broken engagement.
The carriage suddenly accelerates violently, and Isabella fears for her life, suspecting an attempt to kill her to further destabilize the succession. She succumbs to terror and loses consciousness.
Isabella awakens in an unfamiliar room, finding herself in the body of a baby. The woman who found her, with light pink hair and brown eyes, is her new mother. Isabella has been reborn as Aria Lauren in the Kingdom of Mizunowar, far from Monfort. She retains her memories and sophisticated demeanor, causing her parents to believe she is a reincarnation of a noble.
At three years old, Aria struggles to suppress her former noble upbringing, her perfect speech and manners appearing even in casual settings. By five, she is doted on by her loving father. A newspaper headline about the Monfort Kingdom's new Crown Prince triggers Aria's memories of her past life.
Meanwhile, in Monfort, Brad faces his father, the King, who reveals the truth about Lily's supposed sainthood. The King explains that Lily is not the chosen saint and that a younger girl with stronger light magic has been secretly protected as the next candidate. He chastises Brad for his foolishness, stating that Isabella's actions were not out of jealousy but a desperate attempt to prevent his ruin. The King reveals that the engagement was a political contract, and by breaking it and causing Isabella's death, Brad has voided the Toulouse Duchy's support. Brad's aides, realizing their precarious position, confess to having distanced themselves from him. Theodore Toulouse, Isabella's brother, confronts Brad, accusing him of her murder and declaring the contract between their families null and void. Theodore warns Brad that his support is lost and that the succession will be contested. Brad, realizing his precarious position, considers marrying another powerful noble to secure his claim, unaware that no one would ally with him after his actions.
Aria, now six, has mastered her refined speech and is practicing a more casual way of speaking. She has also discovered she possesses light magic, a rare and valuable skill. This leads to numerous marriage proposals, which are halted by the influential Guevres Border Count family, who feel responsible for Aria's awakening of magic due to their son, Theodore's, accident. Theodore, who was saved by Aria's magic, is now frequently at the Lauren residence. He recalls meeting Aria as a baby and being struck by her noble demeanor.
Aria's light magic is registered at the temple, and she is advised to use it sparingly until she is ten. The temple priest, however, immediately tries to arrange a marriage between Aria and his grandson. The Guevres family intervenes, proposing a betrothal between Aria and Theodore, not out of pure goodwill, but as a strategic move to secure Aria's valuable magic and leverage their family's influence. Aria understands this is a temporary measure.
The story concludes with Aria continuing to adapt to her new life, while Brad's reign as Crown Prince is implied to have ended due to illness and a succession war, ultimately leading to the rise of the youngest prince.
