The story begins generations before the plot proper, with the House of Trovi, a noble family whose daughters have a tradition of marrying into the Eastern Empire's imperial line. It's this tradition that leads Emperor Osis III to handpick a young girl named Navier Ellie Trovi to become the future wife of his son, Crown Prince Sovieshu Vict. The two are already distantly related through Sovieshu's mother's side of the family, and despite the marriage being arranged for political reasons, they grow up as close childhood friends. Navier sneaks out of her family estate to see him under a secret code name, "Sir Leedy," and the two get into all sorts of mischief together, including a running habit where she swats him with a pillow whenever he teases her, which is actually how the two of them end up sharing their first kiss. As a child, Navier plants a tree in the imperial garden as a personal symbol of wanting a harmonious future marriage.

One incident from their youth quietly poisons the rest of the story without either of them realizing it at the time. As children, Sovieshu steals a batch of cookies that his mother, the Empress, had been planning to send to Countess Sophia, a concubine belonging to his father, Emperor Osis III. He and Navier eat the cookies together as a childish prank. Afterward, his mother tells him the cookies had been laced with an abortion-inducing drug, one that also carries a risk of causing infertility, meant to be slipped to the concubine. Not wanting Navier to get in trouble, Sovieshu lies and says he ate all of the cookies alone. He never tells Navier the truth, and the secret eats at him for years, because he grows up believing, wrongly, that the drug is what left him unable to have children, and that the reason is something he can never confess to her.

As they grow older, Navier is groomed intensely to become the ideal empress: composed, disciplined, brilliant at governance, trade, diplomacy, security, and public welfare. She earns the nickname "Ice Queen" for the calm, controlled front she presents to the world, even though privately she was mischievous and full of personality as a girl. Meanwhile, Sovieshu grows into an emperor who is capable in his own way but increasingly restless, jealous, and insecure once their marriage becomes an actual working political partnership rather than the playful friendship of their youth. They never openly discuss their feelings for each other, and this silence causes both of them to quietly believe the other doesn't really love them, when in truth, buried love does exist beneath the growing tension. Sovieshu remains convinced, because of the childhood incident, that it is Navier who is infertile, and years of trying for a child with no results only reinforces that false belief.

Desperate to produce an heir and secure his dynasty, Sovieshu devises a plan that becomes the central catastrophe of the entire story: he decides he will divorce Navier temporarily, install a concubine to bear him a child, and then, once the succession is secure, quietly discard the concubine and remarry Navier as if none of it had happened. It is a plan built on the assumption that Navier's feelings don't really matter and that everything can be neatly undone later, and it completely fails to account for how much damage it will actually do.

The concubine in question is Rashta Ishka, though that isn't her real background at all. Before the story begins, Rashta had been sold into slavery by her own father as a way of avoiding paying for his own crimes, and abandoned again even after his debt was settled. For most of her life she belonged to the Rimwell estate, where she fell in love with Alan Rimwell, the heir of the family who owned her, and became pregnant with his child. Alan's father, Viscount Lotteshu Rimwell, was furious at the idea of a slave bearing his son's child and, to control her, faked the death of her newborn son, telling her the baby had died and handing her a dead infant to hold so she would believe it. In reality the boy, later named Ian, was alive, hidden away by Lotteshu as a tool to blackmail her for the rest of the story. Devastated and believing her son dead, Rashta eventually decides to run away from the estate. She begs Alan to come with her, but he refuses, unwilling to risk his inheritance, so she escapes alone with help from a fellow slave named Phix, who loses an eye helping her get away. While fleeing through the wilderness she gets caught and injured in one of Emperor Sovieshu's hunting traps. He has her brought back to the palace to be healed, becomes captivated by her fragile, "innocent" beauty, and quickly makes her his concubine, setting the entire tragedy in motion.

Rashta initially tries to get close to Navier, admiring her and mimicking her mannerisms because she's heard "the empress is kind," but Navier keeps her at arm's length, partly out of the natural resentment of having her husband's concubine forced into her life, and partly because Navier, despite her overall sense of justice, holds classist views that make her comfortable with the existence of slavery even while she personally objects to concubinage. Their relationship curdles from awkward tension into real hostility, especially after Navier's fiercely protective older brother, Kosair Trovi, secretly poisons Rashta's food with an abortion-inducing drug and violently interrogates Lotteshu for blackmail material, all in retaliation for how Sovieshu is treating his sister.

As Sovieshu falls further under Rashta's spell, he begins neglecting and humiliating Navier constantly: favoring Rashta publicly at court events, undermining Navier's own diplomatic projects out of petty jealousy whenever she grows close to other men, and blaming her unfairly for tensions involving his concubine. Navier, ever the professional, refuses to fight him openly, choosing instead to maintain a unified front for the sake of the empire, even as her marriage disintegrates. Meanwhile, Rashta, now pregnant with what everyone believes is Sovieshu's child (though the baby is actually Alan's, from before her escape), begins scheming to secure her position by any means necessary. She spreads rumors that ruin the marriage and reputation of a noblewoman named Nian Tuania, causes public chaos at diplomatic functions to appear sympathetic, and borrows a large sum of money from a foreign noble, Duke Ergi Claude, to pay off Lotteshu's ongoing blackmail. In exchange for the loan, Ergi later demands she sign over a strategically valuable port, a decision that becomes a major political scandal for the empire. Unbeknownst to Rashta, Ergi's motives are much darker than simple opportunism: his mother, Alicia, had been exiled by Sovieshu's regime years earlier, and Ergi is secretly nursing a long-term revenge plot against the empire, using Rashta's rise as a tool to guarantee an eventual, spectacular fall that will embarrass Sovieshu.

Around this time, at a New Year's festival, Navier meets Prince Heinrey Lazlo of the Western Kingdom. Heinrey has a reputation as something of a playboy, but the truth is he becomes utterly infatuated with Navier from the moment he lays eyes on her, and because she's married to another emperor, there's little he can openly do about it. He begins courting her in secret, primarily by shapeshifting into a small golden bird that Navier comes to adore as a pet, naming him "Queen," using this form to deliver anonymous love letters and to simply be near her without arousing suspicion. Over time their bond deepens into real friendship and eventually real love. It's worth noting that Heinrey's motives aren't entirely pure at first either: he originally intends to exploit growing instability in the Eastern Empire to benefit his own kingdom's position, even orchestrating events to expose Rashta's lies and worsen the political situation there, but his calculated scheming gradually gives way to sincere feelings for Navier that eclipse his original political agenda. He even confesses that if he had been her husband, he would do anything to make her happy.

A number of side plots unfold across this stretch of the story. A grand duke from the Kingdom of Luipt named Kaufman, arriving to arrange trade deals with Navier, takes pity on her situation and gifts her a love potion he brewed himself, meant to make her life easier. Wanting to prove it's harmless, he tests it on himself first and, having badly misjudged its potency, becomes obsessively infatuated with her, at one point even threatening both Sovieshu and Heinrey when they get too close to her, and later drugging Heinrey into falling for Navier's sister-in-law Krista as a jealous act. Eventually Kaufman gets a grip on himself, becomes genuinely useful to Navier as an ally in court politics, saves her life at one point from an assassination attempt by a rival family, and helps connect her with a mage named Dolshi to train her burgeoning magical abilities. Around the same period, Navier is exposed to magic stones and discovers she's a late-blooming ice mage, something almost unheard of for someone her age.

The paternity of Rashta's child becomes a flashpoint: a priest, bribed by Rashta's side, falsifies a paternity test to declare Sovieshu the father, buying her more time and protection at court, though the truth about the child's real parentage will eventually surface and destroy everything. Sovieshu, for his part, begins to suspect that he himself may be infertile as strange symptoms and revelations pile up, and this guilt starts manifesting as hallucinations. At one point Navier is brutally attacked by the family of a political rival and falls into a coma; upon hearing the news, Sovieshu is so distraught he falls from a window and slips into a coma of his own, during which the two of them share a strange, telepathic dream-like connection that both later dismiss as just a dream, unaware it was somehow real.

Eventually, having reached her breaking point, Navier travels to the magical city of Wilwol, heartbroken over the state of her marriage, and there she runs into Heinrey. In a moment that will define the rest of the story, she proposes to him not out of romance but out of pure pragmatism: a marriage of convenience in which they would rule as equal partners, and in which she promises not to interfere if he takes concubines of his own, so long as her position as his wife remains secure. Heinrey, who is genuinely in love with her and would gain far less politically from marrying her than he could from a more strategic match, accepts immediately and without hesitation.

Everything converges at the formal divorce hearing, presided over by a High Priest who clearly disapproves of the whole affair. Sovieshu goes through with divorcing Navier so he can elevate Rashta, per his original secret plan. When asked to confirm the divorce, Navier accepts without protest, stunning the entire court, who expected her to fight it. But then she delivers the second, far bigger shock: she requests approval to immediately remarry, and when asked to whom, Heinrey makes a dramatic entrance into the hearing itself, revealing that he has been present the entire time, and moves to stand beside her as the room erupts into chaos. Sovieshu's carefully laid plan to eventually take Navier back has just been permanently destroyed by his own actions.

Navier relocates to the Western Kingdom, which is soon elevated to an empire in its own right, and begins her new life. What started as a practical, unromantic arrangement with Heinrey slowly transforms into genuine love and eventually monogamous devotion on both sides, a stark contrast to the emotionally guarded, transactional nature of her first marriage. For the first time, Navier begins to open up emotionally, supporting Heinrey through his own hidden trauma, most significantly the guilt he carries over having accidentally killed his own brother during a shapeshifting incident gone wrong. As empress of her new nation, she thrives, securing important trade agreements (including one with the Kingdom of Luipt that Sovieshu had spitefully sabotaged out of jealousy back when she was still married to him), averting wars through diplomacy, integrating former bandit groups into society as citizens, and continuing to develop her ice magic abilities. She and Heinrey eventually have twins, a mischievous, strong-willed daughter named Lari and a son named Kai, both of whom inherit their father's shapeshifting ability, something the family keeps a closely guarded secret. Navier becomes a devoted, hands-on mother despite her heavy duties as empress, closely monitoring her children given both their magical nature and Lari's tendency to get into trouble.

Back in the East, everything Sovieshu built collapses in on itself. At one low point he briefly imprisons both Navier and Heinrey and accuses Heinrey of having seduced his ex-wife, but as Rashta's crimes, including embezzlement and outright treason, continue piling up and becoming public knowledge, he's forced to confront the reality of what his scheme actually cost him. Rashta does ultimately become empress as originally planned, but the position doesn't bring her the security she hoped for. Ergi, having used and manipulated her the entire time as part of his long-simmering revenge plot, ultimately turns on her decisively: during the official paternity trial for her second child, Glorym, he secretly brings forward evidence, including producing her long-hidden first son Ian, and rigs the test results to expose that both of her children were actually fathered by Alan Rimwell, not Sovieshu. He then exposes her entire criminal and personal history to the empire through journalists, revealing he was never her ally at all. It's also revealed separately that the couple who had posed as Rashta's noble adoptive parents throughout the story, the Ishkas, were paid actors hired by Ergi, and disturbingly, that their actual biological daughter is Evalie, the young mage that Navier had personally sponsored and mentored back when she was still Eastern Empress; Rashta had at one point manipulated the Ishkas into harming Evalie via a staged carriage accident out of fear that Evalie might become a rival concubine, a betrayal that leads the Ishkas to disown Rashta entirely and testify against her at trial.

Once the true paternity is exposed, and with her mounting crimes now impossible to hide, Rashta is arrested and put on trial for treason against the empire and the emperor. Her mental state, which had already been deteriorating into paranoia as her past began catching up with her, collapses entirely; in her final days in prison, she hallucinates about all the people she wronged and the traumas of her past, eventually convincing herself in her final delusional moments that everyone she hurt has forgiven her and that she's reunited happily with her children and the son she believed died at birth, dying with a smile on her face after swallowing a suicide pill smuggled to her. Her body is cremated on Sovieshu's orders, and her ashes are scattered to the wind. Priests perform a funerary ritual meant to grant her soul peace, a quiet, somber acknowledgment of just how badly the entire situation had gone.

Sovieshu himself doesn't come out of this unscathed. He eventually confirms that he, not Navier, was infertile all along, a revelation that destroys the entire justification for everything he did. The guilt and shock send him into a coma, and when he wakes, he's lost portions of his memory, at times believing he's still the young crown prince and attempting to romance a version of Navier who no longer exists in the way he remembers, even at one point asking the now-remarried Navier to become his secret lover, not fully understanding the current reality. When he later encounters Navier's daughter Lari and realizes how closely she resembles her mother, it deeply unsettles him, since he had once dreamed of having a child with Navier who looked just like her. As he slowly regains a more stable grip on reality, genuine, aching regret sets in, and he spends the remainder of his story trying to foster peaceful diplomatic relations with the Western Empire, driven by guilt and lingering love for the woman he lost. Navier, for her part, writes him a letter saying that while she hopes he governs well, she cannot bring herself to wish him personal happiness, an admission that she still carries the hurt of what he did to her even years later, even as she remains willing to cooperate with him politically for the good of both nations. Because Sovieshu refuses to remarry a third time, and because his mental instability leaves him unable to properly rule, the Eastern Empire's throne effectively passes out of his hands: Duke Trovi (Navier's father) governs as regent, and Lari, Navier's daughter with Heinrey, is eventually named heir to the Eastern throne as well.

Beyond this central arc, the story continues into a number of side stories set after the main climax. One expands on Evalie's connection to the Ishka couple and reveals a kidnapping subplot involving her biological sister and a group of bandits, eventually resolved through the efforts of another character named Lebetti and further integration efforts led by Navier. Another delves further into Ergi's backstory and the psychological wounds left by his mother's exile that drove his long game against the empire. A further arc jumps ahead in time to show Lari and Kai as teenagers: Lari, engaged to a character named Yongyong (the son of two other side characters, McKenna and Dolsey), inherits the Eastern throne and briefly considers ruling both empires before choosing to cede control of the West to her brother Kai instead. Glorym, Rashta's daughter, grows up to become a kind-hearted knight and, upon learning the full truth of her complicated parentage later in life, comes to acknowledge Sovieshu as her father figure regardless of the biology, calling him "dad." A few smaller character threads, involving side characters like Cici and Charles, are left intentionally more open-ended.

Finally, there's a separate spin-off story called "Sovieshu's Regression," which imagines an alternate, wish-fulfillment version of events. In it, an elderly Sovieshu, still haunted decades later by everything that happened, including his treatment of both Navier and Rashta, discovers a magical pocket watch that sends him back in time to the moment right before the original divorce. Given a second chance, he cancels the divorce outright, confesses that he genuinely loves Navier, and grovels for forgiveness. She initially assumes he's lost his mind, but softens after finding him crying in his sleep, begging her not to leave him, and the two of them slowly rebuild a relationship, ultimately remarrying and living what appears to be a happy, loving life together for the next decade, sharing living quarters in a way they never did during their original cold, dutiful marriage. However, this spin-off is treated more as a hopeful, almost dreamlike alternate timeline than a definitive "true" ending, and the story leaves subtle hints that Sovieshu's old patterns of behavior might resurface even in this second chance, deliberately avoiding giving him a fully clean, uncomplicated redemption.