One morning, Celestina, the second daughter of a marquess family, suddenly vanished without a trace. Although the second prince, who held feelings for her, searched desperately, when he arrived at the marquess household, he found that—strangely—only Celestina’s existence had been “forgotten.” Her family acted as if she had never existed in the first place. Amid this mystery, it is revealed that Celestina is a rare being known as a “Snow Moon Flower of Windaria,” one that could alter the fate of the entire kingdom...!? What is the reason she hid herself—and what mission does she secretly bear in her heart?