Looking at the DM Screens map again, I noticed the only location in the Old Empires Region noted by it, is the Untheric city of Messemprar.
Messemprar was once the biggest city in Unther, but it had been in decline when a group called Northern Wizards had taken it over when Gilgeam died. After that eventually Mulhorand conquered it, but six years later the Spellplague happened and city drowned. Then it became a Sahuagin city (the Sahuagin Kingdom of Aleaxtis is right off the coast of Unther, so when the water rose abd swallowed the city, Aleaxtis was able to claim it as their own).
Perhaps of the of the adventure none battle maps is set in Messwmprar or maybe AiF has an mini adventure set there or both.
Curious if it's ruins or if they rebuild the city.