Since the Lonely Tower has proven surprisingly popular, I thought I’d post the ideas I had while designing this dungeon.
Mechanically, the way the dungeon functions is this: everything starts off inanimate. Rooms 8 and 9 are hermetically sealed (and, should the players be skillful enough to notice, are the only rooms with airtight doors and no windows) and filled with a nefarious gas. If the party moves into the Chamber of Horrors (8) without shutting the doors behind them as they go, the gas will move into the rest of the prison, animating whatever various corpses and skeletons it comes across. I don’t think opening the Salon (9) would wreck as much havoc, since the gas is probably lighter than air and therefore couldn’t access the rest of the prison.
That’s about it, except to mention there’s a skeleton under the dock (11). This skeleton has a key which unlocks the ‘backdoor’ hatch (10).
The little story I made up about the place goes like this:
A while ago – after Fallcrest burned and/or after the fall of the Empire – there was a political purge, a not uncommon pattern. The lonely tower was where the Inquisition prisoners were incarcerated, tortured, and usually executed.
Eventually, some especially frisky ne’er-do-wells got into some dark stuff and set up a salon within the prison itself! With the aid of some magical runes and slapdash alchemy, they constructed an infernal device which would refine the agonies of the condemned into a recreational drug. Prisoners below would be tortured and the hedonists above would be able to toke off the distilled, etherized suffering of the condemned.
Everything was fine until everything went wrong and now, 90 years later or so, we have this chamber of horrors waiting for our heroes.