Shadow of the Moon, the Sea of Shadow

The Shadow of the Moon, the Sea of Shadow is the first arc of the Twelve Kingdoms anime. It is primarily based on the first book of the series, The Twelve Kingdoms: Sea of Shadow (with a brief segment including a plot line from the third book, The Twelve Kingdoms: The Vast Spread of the Seas), and introduces the world of the Twelve Kingdoms and a number of major characters in the series. The anime expands the novel's perspective by including Yuka Sugimoto and Ikuya Asano as travellers to the Twelve Kingdoms to be foils and to externalize the struggles felt by the protagonist, Youko Nakajima.

Youko Nakajima, an ordinary high school student who tries hard not to stand out and cause trouble, is suddenly spirited away to a place called the Twelve Kingdoms along with classmates Yuka Sugimoto and Ikuya Asano when she is forced into accepting a pact from a mysterious man called Keiki.

As the trio struggle to survive in the new world and attempt to find Keiki, they become separated and turn against one another when it becomes apparent that only Youko was meant to come to the Twelve Kingdoms. Sugimoto, the only one who wants to stay, becomes a puppet in a conspiracy in which a despairing king desperately wants to kill Youko before she learns something important about herself. When Youko and Asano are separated, Youko is forced to struggle on her own and find her own way in the world where she has no allies.

Characters

 * Youko Nakajima, the protagonist of the series, an ordinary schoolgirl who desperately wants to stay out of trouble and return home after being spirited away to the Twelve Kingdoms
 * Keiki, a mysterious man who recognizes Youko as his master and forcibly brings her to the Twelve Kingdoms, but is separated from her before he can explain why
 * Yuka Sugimoto, Youko's classmate, an outcast who thrives on fantasy novels and believes it is her destiny to come to Twelve Kingdoms
 * Ikuya Asano, Youko's childhood friend and classmate, as well as Sugimoto's boyfriend, an apathetic young man who finds himself divided between his loyalties to Youko and Sugimoto
 * Rakushun, a Hanjyuu, an individual who is physically half-human and half-beast, he becomes Youko's first true friend in the Twelve Kingdoms
 * King Kou, the ruler of the kingdom of Kou, who desperately wants to kill Youko
 * Kourin, the advisor of the King of Kou, who tries in vain to dissuade him from trying to kill Youko
 * Enki, a boy observing the events in the kingdom of Kei who suspects the current ruler is a pretender to the throne, revealed to the advisor to the king of En
 * Shoryu, the king of En, observing the events in the kingdom of Kei
 * Bishin, Kuyo, and other travelling performers
 * Ritsuko and Masashi Nakajima, Youko's parents