From publisher blurb:
5th Edition Mini-Dungeon for four characters of level 11
The modern marvel of Terrendare was not always so prosperous. When the great port’s piers first thrust out against the waves, the elemental storm lord Cirrumos took notice. When the fleets of Terrendare crossed into his territory, however, the mighty elemental took affront. Seeking to rid his domain of interlopers, Cirrumos called forth a raging tempest. And once the skies cleared, Terrendare had been wiped from the face of the earth. Or so Cirrumos believed.
In reality, the storm lord had been deceived. The mage lords of Terrendare had devised a unique form of imprisonment, trapping the unwitting elemental in a miniature replica of his watery domain. For one hundred years now, Cirrumos has dwelled happily within his ‘unspoiled demesne.’ Unfortunately, he is finally beginning to suspect that something is amiss. And that suspicion is playing havoc with Terrendare’s public utilities.