Matsurika Kou is a female officer working in the Inner Palace of the imperial court. Though she began her career as a lowly palace maid, her exceptional memory helped her rise to her current rank. Now sixteen years old and missing her chance at marriage due to palace restrictions, she has accepted a peaceful life of hard work. However, her quiet routine ends when her superior asks her to act as a practice partner for a nobleman's arranged marriage meeting. Upon arriving, she discovers the prospective groom is not an aristocrat but Emperor Hakuyou himself, the eighteen-year-old ruler who wished to try a matchmaking meeting for himself.

The setting is the kingdom of Hakurou, one of four nations born from the collapse of the great Tenkou Empire. Each country is protected by a divine beast, with Hakurou under the guardian spirit Byakko. The capital features the Long Moon Palace, a gleaming white structure where government affairs are conducted in the southern section while the Inner Palace in the north houses the emperor's consorts and female officials. Emperor Hakuyou is no ordinary ruler. Originally a prince without powerful backing, he relinquished his succession rights and passed both the civil and military examinations before his father's sudden death placed the three-year-old crown prince as heir. The imperial family and ministers chose Hakuyou to take the throne instead, and he has since ruled with intelligence, politeness, and a quiet sense of duty that has earned absolute trust from the people.

Impressed by Matsurika's quick thinking and her remarkable memory, Hakuyou does not simply court her. Instead, he issues an unexpected command: go pass the imperial examination first. This challenge transforms Matsurika from a content but overlooked lady-in-waiting into an aspiring state scholar, a path that forces her to navigate the complex hierarchies of court politics, rival officials, and her own growing feelings for the emperor. The story follows Matsurika as she studies for the rigorous examination, advised and sometimes hindered by figures such as Shou Shunsetsu, an Imperial Academy student placed in charge of her, as well as Hakuyou's close aides Hou Shisei, a genius who earned top marks on the civil exam, and Rei Tenga, from a distinguished military family.

As Matsurika rises through the ranks, she must balance her identity as a commoner who was never meant to stand beside the emperor against the expectations placed on her by the court. Hakuyou, who appears as a perfect ruler with silver hair and golden eyes, hides a more calculating and demanding nature known only to his inner circle. The narrative builds through several arcs, beginning with Matsurika's unlikely encounter and the challenge to take the examination, followed by her struggles with court examinations and political maneuvering, her growing bond with Hakuyou as she proves herself, and ultimately the complications of a relationship between an emperor and a woman who must earn her place not through favor but through genuine achievement. The anime is scheduled to premiere in January 2027.