Long ago, in the days of the kingdom of Oberon, strangers came from out of the badlands, dressed in odd garb and speaking an unknown tongue.
When the wizards deciphered the speech, the men had this story:
They came from a far away land, a land of never-ending summer; they had been lost in a cave. Some of their number died escaping a deadly spirit, and they were forced further into the caverns. Finally, they came upon a huge cavern, filled with monstrous mounds that glowed in the torchlight like a thousand rainbow huts. They found a map to guide them to another exit, and escaped upwards through more caverns, losing more friends to a hideous monster on the way up.
Finally, they came back into the open, but in the cold, desolate, harsh badlands, in early fall.