Coldsnap was a throwback expansion, claimed to be a file "found" many years as a 3rd set in the Ice Age block. To that end, Wizards developed the set, and had the author of the Ice Age story block, Jeff Grubb, write about it. He wrote this story, about the goals of Heider, a winter mage hoping the eternal ice would remain eternal. The story is set after the events in the Ice Age Trilogy, after the conclusion in "The Shattered Alliance". Heider is a new winter mage hoping to stop the warming world climate, and keep the eternal ice age going.
This story was originally published in the Coldsnap player's manual, and here it is again for all to read.
Clicking on the images will bring up a larger image, so the text is more readable.
And here is the Storyline synopsis.