Hikari, a young woman, was abruptly summoned to a fantasy kingdom as its Saintess. Initially bewildered and longing for her home, she reluctantly agreed to join the Hero's party to defeat the Demon King, swayed by the suffering of the people and the kindness of the King and the handsome Prince. Over six grueling months, she developed strong feelings for the Prince, who consistently offered support. After the Demon King's defeat, the kingdom rejoiced, and Hikari anticipated her return home.
However, during the commendation ceremony, the King revealed that there was no magic to send her back. Hikari realized she had been manipulated, as the promise of return was only implied, never explicitly stated. Her trust was shattered further when the Prince admitted he had known all along. Overwhelmed by betrayal, anger, and despair, Hikari confronted them, then disappeared from the castle, spontaneously acquiring transfer magic in her emotional distress.
Four years later, Hikari lives a solitary life in a remote region of a different country, running a treatment clinic using her healing magic. The first two years were spent in a daze, the third in reluctant acceptance, and the fourth in building a new life. She has become cynical, distrustful of others' kindness, and prefers isolation. Her unique Saintess powers, which cause fruits to grow and crops to harvest quickly, aided her survival.
Her fragile peace is shattered when the Prince appears at her clinic, persistently kneeling outside for three days in a formal apology. Hikari, still deeply resentful, avoids him, using her transfer magic to move around. She reflects on her past passive nature, realizing how she was exploited, and harbors fantasies of revenge. When she finally confronts him, he apologizes, causing her to instinctively shatter a cup in her mouth. The Prince, despite her hostility, swiftly heals her. He admits his apology is for his own satisfaction and then asks her to return to the castle. Hikari responds by delivering a powerful roundhouse kick to his stomach.
Days later, the Prince remains, now observing her from a distance. Kieth, the talented but naive mage from their former party, arrives, grabbing the Prince, now identified as El, by the collar. He reveals El has been absent from the castle for a month without permission, using a rare transfer magic nullification item to avoid being taken back. Kieth, largely unaware of the full extent of Hikari's betrayal, asks her to return to the castle, believing everyone misses her.
Flashbacks reveal Hikari's traumatic journey: her initial inability to kill monsters, El's injury protecting her, and Kieth's desperate plea after showing her the true devastation of monster attacks (a makeshift hospital and a graveyard). This forced Hikari to suppress her emotions and become a killer, fearing she would be deemed "unnecessary" and replaced by another Saintess if she failed. She also recalls moments of El's past kindness, now viewed through a lens of suspicion and manipulation. The kingdom's fairy tale of a Saintess who stays and marries a hero starkly contrasts with her reality. Now, with Kieth and El inside her home, Hikari struggles to maintain her emotional defenses, questioning the sincerity of past memories while reaffirming her decision to protect her heart.
