The player's mission is to save the people of the Western Tribes that have been captured by the evil Mad Jakk. To do so, they'll need to explore a magic world of flying islands (loosely inspired by the Far West) to recover their sacred treasures and face the brain games left by Mad Jakk along the way to free the people from the different Tribes.

Besides a more poetic background and storyline, OOBLADA told that they have put a lot of effort in improving gameplay and graphics. Treasure City offers brain games to unlock the treasures found on maps, replacing the more 'arcade' styled mini-games of Treasure Madness. Among the other differences is the emphasis on completing missions to drive players through the storyline. Also, a 'love' gauge was introduced that affects the speed at which users can dig for treasures.

Treasure City has been launched as a preview in English and French. New levels and other content will be added on a regular basis.