You all know that something is wrong. You have known that for weeks now, but none of you know the reason. Even those of you with a spark of divinity have been kept in ignorance by the will of greater beings and your meagre insight is shared by all the wise and powerful mortal minds in your world.
The Gods will not answer your prayers and questions, and when you try to reach them you can sense their unease. Fear and frustration builds, both on Oerth and in the heavens, and the peace the world has enjoyed for the last 20 years has begun to fall apart. In the Celestial Imperium, the Tarquish Empire, the Underdark civilisations of the Illithid and the Drow and many other nations, great and small, violence and chaos is once again erupting as a new order begins to overthrow the old. In other nations the change is more subtle and insidious, but undeniable nevertheless. Even as you begin to carve out new empires for yourself the Gods remain silent.
Time passes quickly and the tensions grow. Outsiders begin to gather in the crystal-sphere in ever growing numbers, and though they too share your sense of impending doom they are either ignorant of its nature or refuse to let you know. Even as they align themselves with the great powers on Oerth they remain silent, but for humble whispers urging you to prepare for the worst.
Events accelerate even faster as the first rumours spread like wildfire on Oerth. Incredible and distorted as the stories may be it is clear that forces of colossal power are clashing across the multiverse. Stories speak of a war in both heaven and hell and a sudden upheaval in the Abyss, of something unnameable rising from the unknown depths. They speak of a great rift torn in the fabric of Mechanus, of the Spire falling in the Outlands and the Lady of Pain breaking free from her cage to take her vengeance on her captors. Of Gods falling like wheat before a scythe.
And then the rumours stop, and just after the last hurried refugees take the step across the planar boundaries everything seems to stop.
Reality warps, bends and breaks, and slowly pulls itself back together. The silence in that very first moment is like that of the grave, broken only by a collective cry of anguish from a hundred thousand clerics. They know what you can soon confirm, they felt the breaking of the link with every fibre of their being, the Gods are gone, the Multiverse is gone and Oerth is alone.
For you this is not the end, but the beginning.
Slowly, numbly, the peoples of Oerth return to a life of normalcy. Ignorant, but for a deep sense of numbness and nausea, they return to life. Soon too they will know that their gods are no longer with them, but even so life must go on. Some things change, and some things remain ever the same. They fear for the future, the past, the present, but they can still sense that they have somehow evaded a greater catastrophe. The violence continues, as churches fall and empires are born anew but slowly the world begins to calm, if for but a moment.
The World will never be the same.
Winter is coming to the Flannaes as lone pairs of wanderers arrive at the court of every nation in the crystal sphere. They make no attempt at hiding their diabolic nature and request an audience with the ruler. The devils cooperate fully with any precautions you choose to take but simply state that they have come to offer you their aid. They have vital information that they wish to share, and offer priceless knowledge freely.
The Industrial Revolution is here.