The Irresistible Urge to Fall for Your Enemy

Brigitte Knightley’s debut fiction novel, The Irresistible Urge to Fall for Your Enemy (2025), is the first installment in the Dearly Beloathed duology. In this enemies-to-lovers storyline, Knightley details the grudging alliance between Aurienne Fairhrim and Osric Mordaunt, two magic users who must overcome their mutual hostility and find a cure for a deadly disease. Despite the biases that lie between them, they begin to feel the beginnings of a forbidden romantic desire, but as a deadly epidemic sweeps the kingdoms, they are soon caught in political schemes and the stirrings of war.

The Irresistible Urge to Fall for Your Enemy is expected to be followed in 2026 by a sequel titled The Exquisite Torment of Loving Your Enemy. Explosively popular on social media, the first novel in the proposed duology conforms to the hallmarks of the romantasy genre, which blends romantic conventions with fantasy-style world-building.

This guide refers to the ACE eBook edition published on July 8th, 2025. (ACE is an imprint of Penguin Random House LLC.)

Content Warning: The source text and this guide contain descriptions of violent death, child illness, child death, sexual content, sexual harassment, physical abuse, child abuse, and graphic violence.

Plot Summary

Osric Mordaunt, an assassin for the Fyren Order and a seith (magic) user, is gravely ill. After consulting with two physickers, he now knows that he has seith rot, a degenerative illness that will soon leave him without the use of his seith. This poses a problem because the Fyren Order typically eliminates weak members from its ranks. Desperate for a cure, Osric concocts a plan to bribe Aurienne Fairhrim, a member of the Haelan (healing) Order, to help him. Despite the longstanding history of distrust and disdain between the Fyren and the Haelan Orders, Osric knows that Aurienne is a “phenomenon” in seith system treatments.

When he meets with her, Aurienne initially refuses to help, but Osric offers to make an anonymous donation to the center dedicated to finding a vaccine for the current outbreak of a deadly disease called Platt’s Pox. Hearing this, Aurienne’s superior, Xanthe, accepts his offer to pay 20 million thrysmas, knowing that the kingdom’s nobles have no desire to fund the research needed to find a cure. Aurienne reluctantly assesses Osric’s condition and tells him that his prognosis is dire, as the seith rot is extensive and there is no known cure. However, Osric knows that Aurienne once proposed a theory to use the Old Ways of magic to heal damaged seith systems, and he insists they try it. With Xanthe’s encouragement, Aurienne eventually complies. Using a 500-year-old artifact as a guide, she devises a plan: On given days of the full moon, they will meet in “thin” locations between their world and the Otherworld, and she will flood him with her seith.

Over the next few months, she and Osric grudgingly meet at different locations, bickering and bantering at every meeting, but Osric’s condition continues to degenerate. From the notes of a disgraced philologist, Aurienne deduces new factors to include during her healing sessions. However, Osric, encounters a complication with his illness and soon suffers a seith embolus (clot) that prevents him from using his magic: an immediate death sentence if his order were to learn of this weakness. On her way to treat him, Aurienne witnesses an attack on Swanstone, the fortress in which the Haelan Order resides. When she meets Osric at his family home, she offers a bargain; given that the embolus is likely to reoccur, she asks him to use his skills to find out who ordered the attack on Swanstone. Osric petulantly agrees.

Before he can secure the information, Aurienne calls him for their next healing session at a lighthouse in Muckle Flagga. There, they experience an intensely mystical moment, and the air feels potent with magic. When she administers her seith, the results are still negative, and Osric begins to despair of ever being cured.

On their way back from the lighthouse, they encounter 40 bandits who intend to kidnap Aurienne and kill Osric. The protagonists dispute the morality of murder in this situation, but Osric brutally kills all 40 bandits, deeming the slaughter an act of self-defense.

Days later, when he meets Aurienne again, they measure the progress of his illness. He has also discovered that the attack on Swanstone was  orchestrated by a man name Scrope. Aurienne insists on going with him to extract information on who financed the attack, but Osric refuses.

Not to be deterred, Aurienne masquerades as a sex worker and follows Osric to the unsavory pub where he plans to interrogate Scrope. Despite Osric’s worry for her safety, she approaches Scrope in her disguise and endures his groping and leering until he finally reveals that the man who financed the attack is a wealthy Wessexian lord by the name of Wellesley. Aurienne immediately leaves, and when Scrope threatens to find Aurienne again, Osric kills him with a fork.

Outraged over the murder, Aurienne quarrels with Osric. Later, when Xanthe is made aware of the new intel, she and Aurienne blackmail Osric into infiltrating Wellesley’s Keep to learn more. Osric grudgingly agrees, feeling conflicted about his relief that Aurienne will continue to help with his illness. He is also troubled by his growing attraction to her.

When he next visits Aurienne, he explains that Wellesley has equipped his Keep to ward off Fyren assassins. They are then distracted from this issue by the realization that the latest treatment has stopped Osric’s degeneration. Elated, Osric kisses her hand, and the sensation troubles Aurienne for days.

Wellesley requests that a Haelan make a house call to treat his sick daughter. Aurienne disguises Osric as a Warden, and the two travel to Wellesley’s keep, only to find that his supposedly sick daughter is perfectly healthy. Osric slips into the shadows to investigate further. He finds nothing damning but impulsively steals a bottle of Scotch from Wellesley’s cellar. When they finally meet Wellesley, the man attempts to corner Aurienne into divulging the identity of the anonymous donor who funded the vaccine program (Osric). When Aurienne refuses, the situation quickly devolves. As Osric kills the guards, Aurienne inadvertently kills Wellesley in self-defense. The two slip away before anyone notices, and because Aurienne is a Haelan, they are automatically cleared of any suspicion. Upon examining the Scotch that Osric pilfered, they discover that the bottle contains a suspended form of the Pox virus.

When they return to their respective headquarters, Osric overhears his warchief, Tristane, giving an assignment to his colleague, Brythe. He knows that Brythe is about to attack Swanstone, so out of fear for Aurienne, Osrik kills Brythe before he can go to Swanstone to complete the assignment. Grievously wounded by a knife to the side, Osric makes his way to the home of Aurienne’s parents, collapsing shortly after his arrival. Aurienne secretly nurses him back to health by stealing supplies from Swanstone. Over the following days, she learns of his actions to protect Swanstone and realizes that she holds deeper feelings for him. During her parents’ party, she dances with him and allows him to kiss her.

When Osric is well enough to leave, he returns to his order’s headquarters, only to find that Tristane is suspicious of Brythe’s disappearance. She orders Brythe’s lover, Lady Windermere, to organize a search party and vows to finish the job of attacking Swanstone herself.

Osric plays innocent but quickly rushes to warn Aurienne. Osric and Aurienne deduce that the culprits’ ultimate goal is to resurrect the long-defunct Dreor Order. As they discuss the political ramifications of the plot to spread the Pox to children, they realize that Pox-ridden children are ideal candidates to become part of the defunct Dreor Order (an Order of death-knights who lose all mental stability once they receive their tācn). As they brainstorm ways to foil this plot, Osric realizes that he has fallen in love with Aurienne, but he vows never to speak of it, believing that a romance between them would only lead to tragedy.