Yulia, suddenly dumped by her prince fiancé in front of everyone, is offered as a bride to the Demon King. The shock triggers memories of her past life as 29-year-old Chika, who died from overwork. But in the Demon King's territory, she's given a villa and freedom. With her past life's positive thinking, Yulia embraces a slow life, but her recovered memories reveal incredible saintly powers and other cheat abilities. She improves the Demon King's administration, revolutionizes their cuisine, and accidentally boosts a fluffy cat to a sacred beast level. Loved by the maids and the Demon King's Four Heavenly Kings, she eventually becomes engaged to the Demon King himself. However, the human king and cardinal demand her return, summoning a hero. This cynical hero, however, is more interested in returning to his fulfilling life in Japan. The ensuing expulsion drama involves the Demon King, two saintesses, a prince, and a hero. There will be no malicious schadenfreude towards the prince and the new saintess.