Neverwinter: The Year of Deep Water Drifting
(This location is stolen almost wholesale from the Savage Tide adventure path.)
Aboleth city. The aboleth, except for a few, are trapped in “long dreaming” (cf, 3.5E’s Lords of Madness). Those that are not trapped have turned to Ghaunadaur asking for his/its aid to restore the slumbering aboleth’s slime.
They think the wild energies of the Spellplague might provide a means of escape.