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Deep Carbon Observatory
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Deep Carbon Observatory

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Deep Carbon Observatory is an adventure for Dungeons and Dragons.

The adventure takes players from a town devastated by an unexpected flood, through a drowned land where nature is turned upside down and desperate families cling to the roofs of their ruined homes, hiding from the monstrous products of a disordered world, through the strange tomb of an ancient race, to a profundal zone, hidden for millennia and now exposed, and finally to the Observatory itself, an eerie abandoned treasure palace, where they will encounter a pale and unexpected terror which will seek to claim their lives.

The adventure is suitable for a lucky mid-range party, a stupid high-level party or an exceedingly clever low level party. It is difficult, with a meaningful possibility of character death. Should you find them, and defeat their guardians, the treasures of an ancient culture will be yours.

At the final point of the Observatory is a glimpse of another world.

Deep Carbon Observatory is about 90 pages long, 20,000 words with four maps and extensive artwork by Scrap Princess.

Stats are minimal and given for LOTFP but should be easily transferable into any simple D&D system.

It was created by Patrick Stuart  and Scrap Princess. The layout was by Alex Mayo and it was brought into being at the command of Zzarchov Kowalski


If you prefer top-down maps, Gus L has created some for this adventure for free and Luka Rejec edited them into a more pleasurable form. go here to access them.


Robin Zink at RENFIELDS CAT has actually run it.

"I love this thing. It has introduced myself and a rotating circle of about ten friends to Old School role-playing and we are having the best fucking time."

Basicred RPG

"The phrase "There's a flood and your PCs are compelled to investigate!" is not in the module because it got in the way of poison and rules for the stairs, and because doing awesome things is taken as granted in your players."

"Like many contemporary adventures it’s shock full of desperation and sadness and malice. What makes it stand out, however, is the human scope."

Dungeon of Signs

"Ultimately Deep Carbon Observatory is a thought provoking and wonderful adventure, almost novelistic in its scope and strangeness." ... "Despite my affection for the creator of Deep Carbon Observatory it has troubles. "

Save vs Totalpartykill

"Scrap Princess’ illustrations contribute to the overall tone of the book. I find her work is so frenzied and terrifying. Maybe that’s not the right word, but there is something about how she draws that I find really visceral. I don’t know anyone else that draws like her."

Hack and Slash

The nearest I can figure is avant garde is code for everything in this module is interesting and novel.

Cauldrons and Clerics

Seriously, my points here are - it gives you pretty much everything you need for 4-8 sessions of gaming, depending on your style (my style of games would probably end up at the higher end of that amount) - which for $10 is a steal. (In the same review Luka also goes into some of the negatives.)


This adventure deserves to be spoken about in hushed tones and discrete symbols.

Violent Media

Go buy this fucking thing… It’s incredibly good and very, very interesting.

 Customers Who Bought this Title also Purchased
Reviews (11)
Discussions (3)
Customer avatar
Christopher W November 13, 2019 12:13 am UTC
The link to Gus L's maps seems to be broken. Those maps are available here:
Customer avatar
Jeremy H October 19, 2018 7:28 am UTC
Not part of the Halloween sale? Bummer.
Customer avatar
Alex D September 11, 2017 1:36 am UTC
I bought this with the Relief Bundle, and I see it's for D&D, but which edition?
Customer avatar
Jamie P September 21, 2017 11:43 pm UTC
It's for the older editions (e.g. B/X, the 1981 Basic game) and their retro clones (e.g. Basic Fantasy RPG, Labyrinth Lord, Lamentations of the Flame Princess, Whitehack etc.), most of which can be obtained for free. I expect it also works well enough with 5e, the stat blocks are all simple enough.
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File Last Updated:
July 20, 2014
This title was added to our catalog on June 30, 2014.