Lady Kyriel, the strong-willed commandant of the Alteion Empire, does not want to get married. However, when she finds herself in an arranged union, she is surprised to find that it is with a cordial but mysterious sorcerer named Idwin. He somehow checks all her boxes—the boxes she made sure were impossible to check. Kyriel’s unbreakable vow and Idwin’s inescapable fate take them on a journey to their higher purpose—one that involves the past and future of empires and churches.