The story begins amidst a crisis in the Kingdom of Lewisweek, located south of the Terratrum Continent. A massive horde of monsters, including dragon-kind, has emerged from the north and is advancing south towards the capital city, Visben. The entire royal knight order has been mobilized to defend the kingdom.
Letitia, the current Saintess and Grand Saintess of Lewisweek, witnesses the panicked departure of soldiers from the royal castle. Despite the dire situation, she intends to return to the temple to fulfill her duties. However, she is intercepted by Noah, the second prince of Lewisweek. Noah is a formidable warrior, possessing immense magical power and exceptional swordsmanship, wielding the magic sword Gawain. He is also known for his sharp intellect and proud demeanor. Letitia and Noah share a deeply antagonistic relationship, characterized by constant bickering and mutual disdain, stemming from their equally strong wills and unwillingness to back down.
Noah, believing Letitia should prioritize her safety, orders her to flee. Letitia, insulted by this perceived underestimation of her capabilities, vehemently rejects his command. She asserts her intention to use her unique abilities to protect the country, a role she believes only she can fulfill. Noah, acknowledging her resolve and the fact that she is not one to flee from danger, retracts his order and implores her to use her powers to defend the kingdom. They part ways, with Noah heading to the battlefield and Letitia to the Grand Cathedral.
Letitia reflects on her position as Saintess, which she accepted out of necessity rather than desire, driven by her orphaned status and the financial security it offered. She maintains a facade of grace and dignity, which is known only to her attendant priest, Theodore, who is currently absent, likely aiding the injured. Driven by her motto, "Those who do not work, do not eat," Letitia resolves to perform her duties.
At the Grand Cathedral, Letitia reaches the main prayer hall. The temple is deserted, with all clergy presumably mobilized for the defense. She approaches the statue of Airlat, the god of creation, who is said to grant wishes through the prayers of the Saintess. Letitia intends to create a massive barrier to protect the capital. She prays to Airlat, and a bell signals the god's response. A powerful barrier is erected around the capital, but the immense effort drains Letitia's life force.
She soon senses the barrier being attacked. Realizing that some monsters have bypassed the initial defense, she is forced to expend even more of her life force to maintain the barrier, driven by the thought of her close friend, the Queen, being in danger. She struggles to maintain consciousness as her life force is depleted.
Meanwhile, Noah battles the monster horde. He successfully defeats the monsters, including two ancient dragons, but sustains fatal injuries from one of them. As the monster threat is eliminated, the sounds of celebration reach the temple. Letitia, having expended all her life force, collapses. Noah arrives, also gravely wounded, and finds Letitia near death. Despite their animosity, they share a final conversation. Noah confesses his long-held love for Letitia and his intention to propose after her term as Saintess ended. He asks her to promise to marry him in their next life, to which Letitia, though skeptical of reincarnation and his affections, reluctantly agrees. They pass away together in the prayer hall.
Twenty years later, the story shifts to Letitia Carter, an eighteen-year-old daughter of a pharmacist. She regains her memories of her past life as the Grand Saintess and realizes she has been reincarnated. She is horrified to discover that Noah has also reincarnated as the current King's son, also named Noah, and has publicly declared his intention to find and marry her, believing they are destined to be together. Letitia, now a commoner, is determined to avoid this fate and live a peaceful life. She uses her regained Saintess powers, which have amplified, to alter her appearance back to her original silver hair and blue eyes, but quickly reverts them to her current appearance to avoid detection. She resolves to hide her powers and live as a normal citizen, even considering marriage to someone else to preempt Noah's pursuit.
Three months later, Letitia is working in her father's pharmacy. She has been discreetly using her powers to enhance the effectiveness of the medicines, leading to a surge in the pharmacy's reputation. This attracts the attention of nobles and, worryingly, the possibility of detection by the royal family or temple officials. Despite the risks, she continues to help those in need, unable to ignore suffering.
The following day, a patrol captain arrives at the pharmacy seeking medicine for injured comrades. Letitia's father agrees to help, and Letitia secretly imbues the medicines with her powers. The patrol captain, grateful, leaves his silver nameplate as collateral. The next day, a high-ranking priest named Realim Satisphali arrives with the patrol captain. Realim questions Letitia about the potent medicines, suspecting her involvement in the miraculous recovery of the injured soldiers, which could not have been achieved by normal means or the current Saintess, Katarina. He deduces that the enhanced medicine implies the presence of a new Saintess, and the evidence points to Letitia.
