Here is a quick adventure that I threw together to introduce some players into my Homebrew OSE campaign, using one of Dyson’s creative commons maps. It fit nicely with an existing location on my island of Salmeaus location i.e. the abandoned “lighthouse” on the coast about a days journey west of the city of Falsmouth. That location was always just an abandoned tower, clearly of pre-flood architecture. Locals call it a lighthouse, though it’s original purpose has long been lost. Turning it into an observatory from the old days adds a bit of mystique to the old civilization, who at this point the players have only tangentially been aware of. This spire was built on top of what was a hill with some natural caves below. These caverns connect to some ruins below the waves which have recently been inhabited by a tribe of sahuagin (using merfolk stat block), who delve it for treasure. Hopefully I will get around to doing a narrative write up of this one, since the game actually went relative smoothly. Anyway, enough preamble onto the actual rooms!

1. The Orrery

This room contains an Orrery of high quality, grown rusted with time and disuse. The eastern exterior door is locked, but has been rotted by the constant assault of the sea air. The western wall has a steel rung ladder to the next level of the tower, in the south east there is a trap door to the basement. The smaller adjacent rooms, in clockwise order, are a small kitchen, which is unlocked and contains a single giant crab who is feeding on rotted foodstuffs. Sleeping quarters, with old metal bed frames and shelved. It contains a gas trap which release an acrid, lavender scented smoke into the room. It is cordoned off by hanging wooden beads and has an exterior door to the well outside. The last room is a small ransacked office, with a writing desk and cabinets. Some of the records here my remain and contain information about the location of various stars and planets from when the observatory was active.

2. Workshop

This whole level is dedicated to various tools, charts, and work areas. It reeks of lubricating oils and polishing solutions, even after all of these years. There is an illusion of a Giant Octopus and 400 silver in the south most section

3. Lens Room

This room contains the great telescope lens used for studying the stars. The artifice required to make such is long lost to time, but the delicate crystal array inside may be removed by a successful Find or Remove Treasure Trap. The crystals themselves are worth 500 GP together and can simply be hacked out. However, the entire intact array is worth much more to any enterprising wizards looking to recover such fine work, and may be sold for 2000 GP or more. The intact array weighs only 40 coins and is made up of 40 clear gems (glass) ground into convex circles.

4. Sahuagin Altar Room

This large room features a sahuagin altar to their god of conquest, made out of sea glass and resting on a driftwood stand. It is worth 100 GP, weighs 5 coins, and is protected by a needle trap. The small room to the north was a servant quarters originally, for those who brought food from the city below and filled the cistern at 9. Now it serves as the residence of sahuagin worshippers who are participating in a religious right that involves staying on land for long periods of time, in preparation for their conquering of the surface. At any time there are 2d4 sahuagin here, though they are suffering from dehydration and receive a penalty of 1 to their AC. There is a secret door to the well, which drew water from the cistern below at 9. The well is wide enough for a human to repel down and is 60 ft in depth.

5. Servant dining hall

This room contains a large table, where servants took meals in the old days. There were numerous paintings depicting various events in the observatory’s history, but the sahuagin have pulled down and defaced most of them. A collector might buy one for 100 GP, but they weigh 50 coins and are extremely unwieldy to transport.

6. Bat Cavern

This cavern contains a colony of normal bats, 2d100 individuals are here at any given time. They are somewhat used to the comings and goings of the sahuagin, but may swarm adventures who disturb them with light from torches. Bullseye lanterns may be used, so long as they are night shined directly onto the sleeping bat. The east exit is a 20 ft rocky wall, while the west is a gently sloping natural cavern.

7. Choked Passage Way

This section of cave is choked with growths that resemble sea anemones. Brushing against one release a toxic gas, save vs poison or become blind for 1d10 hours. The growths have a root that may be pulled out of the ground to deactivate them and a path may be cleaned by a single remove trap roll. The sahuagin are immune to this poison.

8. Crab Rave

This room contains 3 giant crabs, circling around a pile of 400 GP and a +1 Sword of Light (cast the Light spell on command). The sword is currently unsheathed and active, distracting the crabs with it’s glow.

9. Ancient Cistern

This pool was the cistern for the observatory, but with the coming of the flood waters has been connected to the ocean through an undersea tunnel. The tunnel is roughly 40 ft long, and only chest high with sea water for most of its length. Is descends at the end and submerges fully, opening out to the ruins of a small city. The Sahuagin have decided to use this city as a staging point for a future assault and are looting it for all it is worth. To prevent anyone from following them, they have posted a Giant Octopus as guard in the tunnel, much to the dislike of the group of nixies who inhabited the pool prior to the sahuagin showing up. The pool also contains the personal horde of a sahuagin raid leader name Whalegullet, (leader) who has taken to obsessively stalking the cave system with 11 of his strongest men, looking for intruders. His horde is quite large, amassed in raids again other sahuagin tribes before coming here. His horde is stored in the center of the pool and the Giant Octopus guards the it fiercely, but will retreat deeper into the tunnel if reduced to less than 1 quarter of its health.

• Horde
  – 3000 Electrum
  – Potion of Diminution
  – +2 Sword
  – 9 Quartzite (50 GP Each)
  – 8 Tigers Eye Beryl (150 GP Each)
  – 1 Ruby (500 GP)
  – 1 Diamond (1000 GP)

Lurkers in the salt soaked caves

The following wandering monster is in effect once the adventurers reach the “natural cavern” section of this map (6 and on). It is checked once every two turns, and monsters appear on a 1 in 6. Resultes 4-6 are unique and should be replaced by 1-3 respectively when defeated or resolved.

1. Group of Sahuagin
2. Giant Centipede
3. Group of Stirges
4. Nixie (wandering from her pool, will ask for help removing the Giant Octopus at 9)
5. Baby Saltwater Croc (as Large Crocodile, but with only a single hit dice)
6. Whalegullet and his 11 guards (if defeated, replace with stirges)

Final thoughts

I hope this little adventure was worth the time it took to read it. I am still working on getting some sort of a commenting system set up, but I have yet to find one that doesn’t spy too much on users. So for now I am still reachable at my email or on some other form of social media, though I rarely check the later. So for now, Sail On!