The aboleths of Xxiphu use an astral collector to funnel arcanic power into an arcanic aquifier and the players are fighting a Kraken and its minions to get to the Mythil that is powering the suspension of the floating city as per canon.
Next session, I need to present 'lesser Aboleths', or the ones who are combat capable.
After the Mythil gets rocked, or collected, the city has to land, which is fine.
wat8.jpg
They can keep the Mythil but the city will land and remain emplaced until they can get another Mythil.
So they keep the Mythil or blow it up (maybe Mactillians meteor swarm already blew it up) and then they have to kill the Aboleth that wanted to target their home, or wipe out All the Aboleth.
The Mythil was a simple objective after some brief travel in a brave new world. Now we do some major boss fighting.