Yun Wangshu's wedding was meant to be the happiest day of her life, but a brutal conspiracy turned it into a nightmare, slaughtering her entire clan. After a narrow escape, she made a desperate deal with the Silent Court. Now, sixty years later, reborn as the merciless Xihe, she's ready to make her enemies bleed for everything they took from her.

Athanasia de Alger Obelia, the only legitimate princess of the Obelian Empire, awakens memories of a previous life; from these, she sees a future where she dies at the hands of her father, Emperor Claude. While his gaze is full of affection for Athanasia's older sister, Jennette Margarita, he only regards Athanasia with indifference and leaves her desperately yearning for his love. To avert the fate that awaits her, the infant Athanasia resolves to escape the palace when she is older and, in the meantime, avoid meeting her father at all costs. However, their paths cross years before it was destined, and so young Athanasia finds herself at the mercy of Claude's seemingly mercurial whims. But the one emotion that she expects, apathy, is never present on his face. With a father who now considers her family, Athanasia strives to grow into a proper crown princess—but her grim vision may yet have ways to become true.

The anime follows the daily life of PuniRunes—mysterious creatures who love to be coddled—and Yuka, a fourth-grade girl who loves soft, squishy things.