Looking for a well-written high-level (10-20) campaign setting in the Underdark from any edition of D&D.

[mrLethol]

Hello! I will soon start to GM "Curse of Strahd", which is for players between level 3 and 10. I want to give the players to continue their adventures with the same characters afterward. It crossed my mind that a high-level adventure in the Underdark will suit this purpose very well since I want to continue with another horror-themed adventure.
But it's very hard to find such an adventure and I have plenty of time. Is there any well-written (preferably official) campaign of any D&D edition that fit this purpose? I will, with the help of the different official rulebooks and with the help of Volos Guide to monsters convert it to D&D 5e. I am happy for all serious suggestions I can get!
Thank you!

 

[Jacob Lewis]

If you can find it.

 

[Joshua Randall]

I can't vouch for how good it is, but...

3e had City of the Spider Queen. It's drow focused.

 

[Zardnaar]

I can't vouch for how good it is, but...

3e had City of the Spider Queen. It's drow focused.

It's not to bad, The Night Below. CotSQ is easy enough to sex up.

 

[Joshua Randall]

CotSQ is easy enough to sex up.

Well it's drow - don't they bring the kinky sex already?

 

[Zardnaar]

Well it's drow - don't they bring the kinky sex already?

No comment. Its a big Dungeon hack.

 

[Haffrung]

City of the Spider Queen would work well. It's for level 10+ PCs, and starts with a dungeon on the surface that would be an easy transition for a horror-based game (SPOILER: a tomb complex). Combat-heavy, but features imaginative and cool enemies and locations. And a lot easier to run than something like Out of the Abyss.

While the Night Below is a great campaign, it's for levels 1-12, with no real real easy way to start with the higher-level content.

 

[Zardnaar]

Labyrinth of Madness is a 2E dungeon technically in the underdark. More of a dungeon complex not much underdark.

 

[Voadam]

If you want official there is the 1970s Gygax Descent Into the Depths of the Earth underdark series D1-3 originally for levels 9-14.

D1-2 Descent Into the Depths of the Earth

D3 Vault of the Drow

There are even already done 5e conversion kits for it which pegs the suggested levels around 12-14.

5e Conversion for D1-2

5e Conversion for D3

 

[S'mon]

Maybe books 4-6 of the Second Darkness AP? https://pathfinder.fandom.com/wiki/Second_Darkness