Second Darkness Campaign
From The Griffin's Crier
Overview
A strange light in the sky holds a danger unknown for ten thousand years! Deep beneath Golarion's surface, the greatest shame of the elves is stirring once more. Seething with hatred, the drow have come up with a plan to wipe out their ancient enemies and bring a second Age of Darkness. And this time, there's only the heroes to stop them...
-- Paizo's Second Darkness Adventure Path description