The PC’s acquire a treasure map, detailing an ancient temple ruin with a secret door marked on the map. The location of the temple can be found in a variety of ways. If they purchase the map, for example, they could simply be told where to find it. If they steal it or find the map, the name of the Temple might be on the map, and they could use that to find out where it is. Regardless, once they have the location, they can travel to the temple and begin to explore its depths.
This adventure is best used for a quick dungeon crawl for lower leveled characters, or as a sidequest during a larger storyline. The only real end to this is when the PC’s are done with the temple itself.
The Temple: Ground Floor
Once they reach the temple they will find the main doors are still intact, however they are starting to show signs of rot. Sturdy doors to be sure. Upon entering the temple they will find a vast cathedral like chamber, with a pulpit at the far end, and a door on each the left and right wall, and a door at the back. There are holes in the ceiling, and most of the wooden pews have been broke and are rotten. The ceiling is at least 50 feet high from the floor. Some moss and other lichen have begun to grow and break the flagstone floor as well.
The door on the right wall leads to the pentitent cells, where sinners were confined to think about their actions. One would have to request confinement and specify a number of days.
The door on the left wall leads to the pastor office, where the secret door is marked.
The door in the back behind the pulpit leads to the kitchen, dining area, and general sleeping quarters.
The office was once a well appointed office for the head priest or pastor. Inside are several bookshelves, 3 on the right wall (upon entering), 2 on the back wall, and 1 on the left wall. An old desk stands towards the back of the room. Once again a hole is in the ceiling, and the ceiling is much lower here, only a good 10 feet high. The rubble from the hole sits in a pile in the floor.
The secret door on the map sits behind the middle bookshelf on the right wall. It is opened by pullin the middle drawer of the desk via a pulley system under the ground. Theoretically one could force it open via a crowbar as well, but that would damage the door.
The desk has some old paper and inkwells in it, as well as some quills. There are no books left on the shelves, having long been looted.
Once the door is open, there is a 5ft wide hallway that leads to a spiral staircase going down 30 feet, into a dark chamber called "The Tomb".
The Penitents Chambers
This area was built much more sturdy when compared to the other area’s. Its dark, the only light coming from the outside group of cells, as they have windows. There are 5 cells on both the left and right side, and none of the doors are locked.
Upon investigation, the first cell on the left side has no window. If investigated further, one would find a secret door on that wall, which would lead down to a hidden corridor. Inside that hidden corrider is a pit trap that cover a 5ft wide area, and spans the width of the corridor. At the end of the corridor is a staircase leading down, to a place called "The Library".
Monks Living Area
There is nothing major of note here. The area has been thoroughly ransacked and the food spoiled and rotten in the kitchen. At this point it is just several blank and empty rooms.
Once down the staircase, there is a small hallway that is 5 feet wide and goes 15 feet before turning to the right. Once inside, there is a room with several torches enchanted to not go out. They are built into the walls and cannot be removed, but provide enough light to light the whole room.
Inside are 9 caskets, arranged in a semi circle. They are plain caskets, and the contents have long since rotted away. Inside of 2 of them are zombies, which upon sensing the living will attempt to get out and attack. It will take them several hours to do this. In 2 others are 2 skeletons, which will attempt the same thing as the zombies, and in one is a giant carrion worm, which has grown too fat to get out on its own.
Inside the one casket at the apex of the circle is a hidden staircase going down another 30 feet by spiral staircase. At the bottom of this is an area known as "The Labs."
There are 3 chambers down here, arranged in a skull shape. Two of the chambers, the Preperation and Reanimation room, make up the eye sockets, while the Storage room makes up the mouth. There is a trap designed to inflict light damage sitting at the first intersection.
The Preperation Room
Whatever priests were at this temple, they were not the good sort. This room was used in the past to prepare corpses and cadavars for reanimation. They corpses were cleaned, stiched up, and then taken to the Reanimation room. Inside this room sits a creature known as an Allip, whose insane babble will unerve and confuse those who hear it. It is the memory of several of the people whose bodies were taken here.
The Reanimation Room
This chamber holds 3 large tables, and a myriad of Alchemical instruments. On the left wall stands a bookshelf next to a desk. On that shelf sits a spellbook containing most low level necormancy spells, and instructions on how to creat zombies and flesh golems.
The tables are build in such a way that they can tilt. There is nothing else to be found here.
The Storage Chamber
This place was once where the various chemicles and new equipment were stored. Currently it is the room to a family of 4 Dire Rats. Also, the door handle to this chamber is trapped to Shock anyone who opens it without speaking the proper command word.
This large cavernous chamber is home to the collected knowledge of this temple. There is a vast amount of knowledge stored here. It also happens to be guarded by several zombies, skeletons, and animated books. They are hidden among the rows and will only attack when someone gets near them.
And that back to the north side, there is a single door which leads to the Artifact Chamber.
Here, anything of value was stored by the temple. Inside there is not much left, except a strange idol. The idol radiates evil.
Guarding this chamber is a Wight, tasked with destroying all who enter who do not speak a command word.
Expanding the scenario
As the idol itself is evil, if the party picks it up it could be that that it actually belongs to a group who is searching for it. By having the idol they become the target of repeated attacks.
Also, there is plenty of room for customizing the temple further, as I have left most of the information intentionally vague. You can add more creatures, and perhaps more treasure.
I am actually using this temple in my current game, and what I am doing is having the idol be an Icon of a Demon Lord who is seeking to enter the world. The Icon’s, when the proper rites are performed and a sacrifice performed, will transfer the lifeforce to the demon. He wants his cult to have that icon, and thus begins sending assassins at the PC’s. He can see through the idol and knows that people are moving it. I say this just give an idea of what you could do with a ancient abandoned temple.