The story takes place in a world ruled by people who possess "Lua," supernatural powers granted by the gods. Ceska, a multilingual speaker who understands every language, attends an academy for the children of royalty and rulers from various nations. She also works as an interpreter. Meanwhile, Shiki, the prince of a nation whose people have no Lua and are called "Yaguu" and endure harsh discrimination, enrolls at the academy. Driven by a desire to befriend Shiki, Ceska actively converses with him, gradually closing the distance between them. However, a certain phrase uttered by Shiki triggers a massive shift in the world… This fantasy weaves its tale around Ceska, a genius linguist, and Shiki, the handsome prince of an oppressed people.