The story begins with the protagonist, Sylvia, recounting vivid dreams of a past life where she was a commander, known as "Your Excellency" by allies and "Blood-Soaked Witch" by enemies during a tumultuous era. In these dreams, she had a particularly troublesome subordinate with unruly red hair, whom she rigorously trained and often berated. This subordinate, significantly younger than her, was initially incompetent, prone to shirking duties and complaining, only showing enthusiasm for wooing women. Sylvia admits to relentlessly pushing him for years, even after he began to improve, until her own death in battle, with him being the last person by her side.
In her current life, Sylvia is the youngest daughter of a Duke, a stark contrast to her past life. Her realization of the dreams being memories solidifies at thirteen when she meets the Crown Prince. Upon seeing him, she immediately recognizes him as her former subordinate. The Crown Prince, Adonis, is equally shocked and confronts her, confirming her memories with the taunt, "The red-haired dog in heat." Sylvia, flustered, tries to deny it, but Adonis, now the Crown Prince, declares his intention to seek revenge for her harsh treatment. He reveals he lived to eighty and, despite his past, is now in a position to propose to her, which she, as a Duke's daughter, cannot refuse. He publicly proposes, claiming love at first sight, much to the disbelief of Sylvia and the uproar of her family, who deem her too passive for the role of Queen.
Six months into their engagement, Adonis confesses his difficulty in enacting his revenge. He admits he prefers proactive women and finds forcing himself upon someone unwilling to be unappealing, especially given the need for an heir. He proposes a compromise: Sylvia must find someone she can genuinely love. If she succeeds, he will mockingly call her a "chestnut-haired dog in heat," laugh heartily, forget the past, and dissolve the engagement, wishing her happiness. This condition stems from the legend of a Saintess who sacrificed her life to save a knight, a story Sylvia, despite her lack of faith, now reconsiders upon seeing the petal-shaped mark on Adonis's hand, a sign of the Saintess's bloodline.
Three years later, Sylvia has failed to find true love, despite Adonis introducing her to many suitable men. He laments her lack of romantic interest, attributing it to her being "too dense." Sylvia, in turn, points out his own past as a womanizer and his current obsession with revenge. Adonis reveals his past as a prince in a brutal era, forced into assassination and espionage to survive. He was sent to assassinate Sylvia, but her relentless training and refusal to give up on him, even when he was at his lowest, changed him. He realized her true desire was peace, not battle. He sacrificed his life to save her, fulfilling her wish for peace by ensuring her survival and the end of the war through a pact with his ambitious half-brother.
Adonis, reborn as the Crown Prince, retained his memories and the mark of the Saintess. He discovered that his half-brother had erased all records of the Saintess and the war, effectively ending the cycle of tragedy associated with the Saintess's power. He believes Sylvia's wish for peace led to their reincarnation in this era, with him born as Crown Prince to protect it. He initially intended to be her guardian and dissolve the engagement once she found love, but Sylvia's passive nature and her casual acceptance of becoming Queen make him fear for her safety, leading him to consider marrying her to protect her himself. He confesses his enduring love for her, a love that has persisted since his past life, and vows to provide her with the peaceful life she desires, even if it means supporting her literary pursuits and ensuring her comfort. Sylvia, however, seems unconcerned with finding love and expresses a desire to become Queen, much to Adonis's dismay, as it complicates his revenge and his plans. She playfully suggests her "stamina" and love for reading are her selling points for becoming Queen, while Adonis desperately tries to get her to take her life and his revenge more seriously.
