From publisher blurb:
Welcome to the twelfth and penultimate adventure in the ZEITGEIST adventure path!
The End Has Already Begun
Things are falling apart. An attempt by the Obscurati conspiracy to create a more perfect world was sabotaged, and the world is descending into chaos. With mere months before the planet is devoured by the cosmic gears of the graveyard of the multiverse, the party undertakes an extraplanar expedition to find the means to fix the conspiracy's disastrous failure.
But there in the Gyre, at the center of oblivion, a primordial serpent known as the Voice of Rot has coiled itself around the physical manifestation of time itself, and it intends to drag the party's world to its destined destruction. The party must slay the rough beast if they wish to hold together their dying world so that tomorrow can be born.
An adventure for psychopompic heroes of 28th level.