This adventure is notable as it is a direct sequel to an earlier one, The Blackguard's Revenge, which told the tale of a bunch of undead attacking the headquarters of an order of paladins. Whether or not your party was involved in that adventure, which (hopefully) saw the undead sent packing, they may be called upon to seal a further crypt to prevent even viler evil powers from getting loose. Trouble is, the crypt in question was designed by the best thieves and wizards money could hire to be impenatrable, and to seal it securely, first they must get inside!
There's a dire warning: the traps in the dungeon are not designed to be survived! So the party needs to take care, there are no convenient escape routes built in. The DM's notes also cover such things as wandering monsters and scaling the adventure for tougher or weaker parties than the 4-6 characters of 11th-13th level envisaged; and provides some suggestions for involving the party particularly if they haven't played The Blackguard's Revenge.
The background explains that the Iron Crypt of the Heretics was built with a three-fold purpose: to house the bodies of the heretical blackguards, to serve as a library for the religious tracts declared by the Church to be false beliefs, and as a storehouse for evil artifacts and cursed magic items brought back by questing paladins. In The Blackguard's Revenge, the first section was breached and the deceased blackguards raised as wights. The other two vaults remain, but the aggregation of evil stuff down there is fermenting and brewing a nexus of great evil... and something needs to be done before it erupts to scatter and cause problems across the land.
As usual, the adventure opens with the party standing outside the Crypt (and despite the dangers probably quite eager to get in, seeing as there's a blizzard howling around them). The whole place, excellently described, is full of traps for even the wary, never mind the unwary, and clear thought as well as strong sword-arms and ready spell books will be required to win through. There's quite a lot of reliance on doing the right thing in the right place... it's often not obvious, and the text suggests the use of appropriate Knowledge checks to 'remember' something about the situation that will provide the necessary information. You may find it necessary to drop hints when rolls are flubbed.
If you like well-described dungeons that are jam-packed with ingeneous and deadly traps, then this one awaits. Everything hangs together well, with the traps being well designed in a mix of clockwork and magic that - if magic existed - could work if you went and built them. Five pregenerated characters are provided, although the layout is messy and to make them usable it's best to copy them out onto a character sheet before use. Good handouts, including a few 'this is what you see' illustrations, and clear detailed maps complete this adventure.
[4 of 5 Stars!]