In 1992, TSR released FMQ1: City of Gold. This combination supplement and adventure brought players north of the fabled lands of Maztica to meet the Azuposi and find the aforementioned City of Gold. The Azuposi themselves were based on the varied Pueblo Native Americans, mixed with a bit of high fantasy.
This 100 page product is meant to be the spiritual successor of FMQ1.
What has happened to the Azuposi since it was last visited? How did they handle the Spellplague? What has happened to all of the loose ends City of Gold left open?
Those questions are answered here, but that is by far not all.