Shiro to Kuro no Alice

Based on an otome game from Otomate.

“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--?