Life is tough for the inhabitants of the Cloudy City, where poverty and corruption are common and the criminal organization of the Lucky Crows spreads terror everywhere. Tosiko, Jun, and Mei Kawakami are siblings who, although not bound by blood, are devoted to each other and live outside the law, seeking revenge for the unjust murder of their beloved "aunt" Reiko.

Haru is the son of the empress, destined one day to become the ruler of the Archipelago and continue his mother’s detestable legacy. However, he is more interested in befriending the magical Spirits of the Sun, who, it seems, are the only ones he can see.

Theo has been forced to leave his homeland and now reluctantly works as a mercenary for the Lucky Crows. He doesn’t want to be a criminal, but as an illegal immigrant in the city, he doesn’t have many options. When Tosiko steals a dragon pearl belonging to the leader of the Lucky Crows, an exciting adventure begins for all of them, one that will determine the future of the city.