From the back cover:
The adventurers happen by just as a dead god is being excavated. Inspired by Quatermass and the Pit. DEAD GOD EXCAVATION is a short adventure for characters between 1st and 3rd level. I think it's perfect for kicking off a gonzo, eldritch, science fantasy campaign. if you incorporate this into your 'session zero"...respect, hoss!
This scenario was written for Crimson Dragon Slayer (including some new rules for clerics), but everything can be easily converted to your OSR system of choice.
LA BAS CHARTREUSE is neither an adventure nor campaign setting, but a place where Lovecraftian horror happens!
There's a Monolith and nearby a stairway down into the earth.
LA BAS CHARTREUSE contains various scenario seeds with specifics that can be used to flesh things out. You'll also find several random tables, a couple of which can be used in many, many investigative horror and eldritch pulp scenarios.
Ideally use this with The Outer Presence.