From the PDF introduction
A web enhancement for Frostburn
A Short Adventure for Four 8th-Level Player Characters
Frostburn introduces a wealth of information for players and Dungeon Masters whose campaigns happen to be set in frozen lands such as the north pole, a high mountain pass, a frozen outer plane, or somewhere equally inhospitable. While these dangerous realms are rife with adventure and would make excellent locations for any number of exciting campaigns, it s not a simple matter to abandon a current campaign and start up a new one. Of course, you could just have the PCs go on one or two adventures set in such a region, eventually to return to warmer climates and the main campaign.
Yet you don't have to make the PCs travel to the distant glaciers or frozen outer planes just to get some use out of this book. Nor do you need to start up a brand new campaign set in the Land of Black Ice, or the Great Glacier, or even Stygia. You can bring the frost to the PCs!
Curse of the Rusty Walrus is a short adventure for 8th-level player characters (PCs). You can use it as inspiration or as a starting point for adventures that utilize the new rules and options presented in Frostburn. As always, feel free to adapt the material presented here as you see fit to make it work with your campaign.