Shiro to Kuro no Alice

Airi had been living her normal, peaceful life in the White World. Luna had been ruling the Black World as the queen. One day, a coup d’etat rose in the Black World, and the two girls were swapped—Airi to the Black World, and Luna to the White World. What is the secret that lies behind these worlds, and what underlying connection binds Airi and Luna?

(Source: Kadokawa, translated)