This is the first of what I hope to be many such posts.
DISCLAIMER: This obviously isn't playtested, nor does it have any stats for the monsters/NPCs.
Idea: An old tomb on the edge of town, in the ruins of an abandoned cemetery, full of undead creatures controlled by a strange faerie.
1. The room contains 8 skeletons in tattered funerary clothes, that push their way out of ornate stone coffins. Their teeth clack in a foul mockery of speech, and they immediately move to attack with their ancient claws. Each skeleton is wearing funerary jewelry. (The jewelry is worth 50 coins per skeleton, 400 in total.)
2. An altar to a patron saint of the dead (St. Agatha the pious, a famous nun of the church who performed burials for free for victims of the plague) is here, with a collection of offerings in her lap. (The offerings are a mixture of minor trinkets and valuables, coming out to around 350 coins in total.)
3. This room contains 4 stone tables, on each one is a corpse in various states of decay. Maggots “eat” at the flesh of them, but instead of consuming flesh, seem to be growing new flesh with each bite. (Any body, partial or complete, left here will be restored to the same level of freshness it had just after death over the course of 2d6 days.)
4. A huge rotting corpse, encased in rusted and blackened armor, sits atop a stone, rune-carved throne, a shining dagger impaled in its chest. (The dagger vibrates when near sources of dark magic. If the dagger is pulled out of the corpse, it will begin to vibrate violently and the corpse will animate into a monstrous undead knight. The knight will speak in a booming thundering voice as it attacks, with battle cries in an ancient, long forgotten tongue. Some runes on the throne he sat on read “Alindir the Giant”.)
5. A sickly, pale woman weeps in the center of this room, which is full of wilted flowers. Her face is covered. (If approached, she will pull her hands away from her face, revealing it to be a skinless and bloody skull. She will then attack. While she attacks she will continue to wail and cry. If she is slain, she will whisper “I forgive you”.)
6. The floor is mostly moist black dirt, though there are “stepping stones” of crumbling brick that lead to the other side of the room. (If the dirt is stepped on, skeletal hands reach out from the ground and attempt to pull the trespasser beneath the ground, suffocating them.)
7. There are some opened coffins, full of the stench of decay, containing naught but old bones. (The bodies are all not complete, and either missing heads, legs, or other parts.) The walls are painted with murals of the afterlife, with the lower half depicting the horrors of Hell, and the upper half depicting the glories of God and heaven.
8. On a strange throne made from bones, sits an alien and eldritch being. It looks like an extremely androgynous human with goat-like legs, pure black eyes, short horns, and pointed ears. It wears an elaborate silver crown stylized to look as though it is made of leaves. (The crown is worth 500 coins. The being on the throne calls itself Aldreth, and is the fey sorcerer who has been reanimating the dead. It is haughty, aloof, and utterly without emotion besides smug confidence. It came from the nearby woods, and is nearly 250 years old. It has a fascination with mortality.) Kneeling before it are 4 animated skeletons, engulfed in a sickly green flame, that obey its every command.
9. There is a large metal box in this room, with pipes and tubes sticking into it. There is a hole with an open lid large enough for a human to fit through. (There is an engraving in an ancient tongue above the hole, that, if translated, roughly means “flesh devoured by fire is purified in the eyes of God”. If any living thing goes into the metal box, the lid slams shut and whoever in the box is incinerated by fire.)
10. The room is a mass grave, and the floor is a tangle of bones and the ragged grave clothes of those who could not afford proper burial. (There is a shovel nearby, and it appears someone was attempting to dig through the pile of bones and cloth.) The walls have names written on them, one for each corpse. (Many of these names are very old, and not commonly in use today, making this room very old indeed.)