Cairn of the Winter King is the adventure provided in Monster Vault in the form of a 32-page booklet. It’s designed for 4th level characters and is a logical next step to Reavers of Harkenwold from the Dungeon Master's Kit. As its title suggests, the players must match wits against the Winter King in order to save the day. The adventure is pretty standard with a quest to be undertaken in order to set things right again. This adventure takes place in the town of Fallcrest, in the Nentir Vale, and in the Cairn of the Winter King.