The anime casts Yoko Nakajima, a Japanese girl who is suddenly transported to another world and eventually discovers that she is the empress of the kingdom of Kei, in the role of the main character; however, in the novels, Yoko is only one of many main characters and her story is focused upon in only two novels.

The anime focuses on the Kingdom of Kei and the events surrounding it. Several of the other countries are introduced, the most prominent being Kou, En and Tai, while Kyou,Hou, Sai and Ryuu play a minor role compared to the other three. The rest of the kingdoms are only introduced by name and a brief description of the current ruler and taiho. The anime also introduced the characters Asano and Sugimoto to accompany Yoko to the Twelve Kingdoms. Their role is to externalize some of Yoko's problems that were internal in the novels.^[7]