"Yui just needs to stay at home and that's it." Married to the man she loves, her days of happiness are about to begin - or so she thought. Yui Segawa, a housewife in Japan, was tired of her distorted marital relationship with her husband, Taishi. One day during a heavy rainstorm, Yui was hit by a truck on her way to pick up her husband and lost her life... Yui found herself reincarnated in another world as Leticia, daughter of the Marquess of Hagner! Letitia receives an oracle from a saint and is ordered to defeat the Demon King with a hero who will be summoned after the Demon King is resurrected. After defeating the Demon King, the saintly woman is rumored to marry the king's younger brother, Prince Cyril, and Laetitia dreams of marrying Cyril. As if betraying such expectations, the summoned hero is...?