The place is Oerth.
The time is the end of spring in 575 C.Y.
The week-long Growing festival was in full swing in the magnificent Jewel of the Flanaess, the City of Greyhawk and you were in the metropolis to enjoy the festivities. This year there was a special attraction, the mysterious gypsy-like Rhennee had, for the first time in record, sailed one of their large house-barges from Nyr Dyv lake and up river Selintan to set up shop on the river margin near the city's walls. You were forewarned of the Rhennee's ill reputation, but curiosity got the upper and you visited they strange tents and its denizens.
What happened next is now a blur and very hard to recall. Maybe you partook in exotic fumes or elixirs, or maybe you were one those that gazed into the interior of mysterious reflecting crystals that a old Rhennee woman vouched would reveal secrets.
Whatever the reason or cause, you have a half-remembered dream of flying on the back of some gigantic bird, so high aloft the countryside below was laid out like a map. Mile after mile the gargantuan avian beat its wings until after some time the open country gave way to a dense forest and beyond this a broad grassy plain. But the goal of that mad flight was further ahead still.
A dark snow-capped mountain loomed up beyond the plain flanked on either side by lesser peaks. Running like a gash down the mountain side, a deep valley sends forth a river on to the plains below. It meanders through great loops until it forms a small lake, then drops over a ledge and disappears into the forest below. The river and lake remind the body and head of a snake, and the image is completed by an isle in the lake like the snake's eye.
Never faltering, the giant bird takes you toward the mountain peak, following the course of the valley. At its mouth is a steamy marsh, above this a grassy meadow, woods and lake, and higher still are two more lakes, icy-blue and bounded by snow-covered slopes. Finally you come to a rocky crag near the peak, where an enormous birds nest perches. Unnatural mists rose out of nowhere then, and everything went grey...then black.
You awake sometime latter to find yourself within the giant nest. This is no dream! The massive structure of tangled trees and branches, with even an old wagon and half a small boat incorporated into it is as real as your hands. The area of the nest where you had been sleeping is carpeted with leaves and straw, and contains many bony remains. Some animal...some human. Of the giant dream-bird that brought you here there is no sign.
A couple other living people are here too, rising from slumber just as you are doing. Perhaps you recognize a face or other from the patrons of the Rhennee tents back in Greyhawk. Before any words are spoken everyone's view is drawn to the magnificent view from the nest. Spread out below is the long valley hemmed in both sides by towering walls of rock. Beyond it, is the winding river. Shimmering in a shaft on sunlight which breaks trough the clouds, it reminds you more than ever of a snake. Just for a moment, before the clouds close over, the light catches the island in the lake, which answers with a sparkling glint like a giant, inviting eye...