This is a small, dangerous dungeon loosely based off of the Lokir's Tomb tutorial series by Bethesda. These halls are not filled with Draugr however, but are inhabited by a cult of necromancers using ingredients from the dead to create noxious poisons.

You can find it west of Anise's Cabin near Falkreath (there's also a location in the screenshots). The recommended player level is 6 and above, but you can definitely finish it at a lower level. While there is no active quest associated with this mod, there is radiant quest support, so you may run into it on your miscellaneous quests.

Let me know if you run into any bugs! I've tested it pretty thoroughly, but you never know. Feedback is greatly appreciated!

UPDATE:
I cleaned up the dirty ITM edits, however the nav mesh changes that you might see in TES5Edit are necessary for companions to enter the dungeon.
As long as you have the hallsofdeath.esp loaded AFTER the base .esp files and any other unofficial patch files, your game should be just fine.