Ingredients
Paladin's holy mount
Gargantuan fire beetle
Crippled rogue
Flooded mine
Diary
Intelligent Greatsword
Another good chestnut from the original Home Game, this one is very difficult to be original with anymore, but I'll try. At 1,600 words, this one ran a bit long, too.
Hanged Man's Diary
Summary: A treacherous tower, trapped in several ways. The PCs get to kick in doors, smack down a few undead, and the DM has an opportunity to put a few riddles in.
Ancient History
Centuries ago, there was a necromancer named Gruenwick with a bad temper and a particularly morbid sense of humor. To provide himself with the solitude he needed to continue his studies into lichdom, he constructed a five story 'tower' deep beneath the earth, connected to the larger realm of underdark by a few byways (to allow minor trade and other acquisitions of need).
How unfortunate, then, that Tom Gallows, on the escape from the nearby drow, snuck into the tower to hide. Tom had never been particularly fortunate in life - he got his last name from a hanging rope that broke and rope-burned a permanent scar around his neck.
When Gruenwick caught Tom, he killed him, thought better of it, raised him, stapled him to a wall by his elbows and knees, and began enchanting. When he was done, the now-crippled rogue was a living diary. Whatever is said in his presence became a tattoo on his flesh, slowly overwriting past text when it ran out of room. Then the necromancer died, leaving Tom stapled to the wall.
Poor old Tom Gallows eventually went mad - the necromancer had made him effectively immortal during the enchanting - and kept himself occupied by repeating bits of the passages he could see on his flesh. Over time, Tom eventually memorized everything there, and as things were added, he memorized those too.
Death of a Hero
Flash forward to the present day. The tower is long forgotten, the cavern byways dusty and unused. Some of the undead that Gruenwick created still roam the halls, performing their chores as they always have. Tom is stuck in the darkness, gibbering short bits of the diary to himself.
And then dwarves, following the guidance of a wand of detection that sensed the presence of a few bits of adamantite in the necromancer's tower, broke through one of the walls and encountered the undead. A number of dwarves died, and they retreated to hire a hero to take care of the undead... so they could get back to work on the mine.
That hero was Janna Lightfinder, a dwarf paladin of great skill and reknown, who hunted undead mercilessly. Her companions, their names lost to time, went with her. Janna mopped up some of the undead handily, until she came across old Tom Gallows, gibbering on the wall. The party began discussing what to do about him, and the conversation ran long...
Tom Gallows snapped into awareness and began screaming, "No! I haven't memorized that part yet! You're ruining the text! Shut up! Shut up!"
When they asked him what he was talking about, it just made things worse, as his skin crawled with new words overwriting the earliest parts of the conversation. He began frothing at the mouth and screamed one of the only two command words he knew... the activation word for one of Gruenwick's gates. Out came a gargantuan fire beetle, filling the entire room, who promptly wiped out the paladin and her party. Janna's mount, a sturdy cave pony, managed to escape and work its way back up to the dwarves. The dwarves nodded grimly to each other when they saw the riderless pony, and began sending out requests for a new batch of heroes.
With blessed silence at last, Tom Gallows began the work of memorizing the new lines that were left to him.
The two command words, incidentally, are "Burning Truth" and "Watery Grave". Burning Truth opens a portal to a fire demiplane, from which a gargantuan fire beetle will come out; Water Grave opens a portal to a water demiplane, from which a large lake's worth of water will pour.
Gruenwick's Greatsword
There is only one other defender of the tower left: Gruenwick's other cruel joke, a greatsword possessed by Mud, a Blackguard who was extremely useful to Gruenwick in life, but failed to make certain he continued to be useful past the first few years of service. Mud's not his real name, of course, but it's the only one he remembers anymore. Bound to float through the halls and defend them against all intruders, Mud is not particularly happy with his lot, and would welcome someone breaking his curse (he will even talk in battle, explaining how they can break it - should they do so, the blackguard will reappear, sword in hand, and attempt to escape).
Meeting Tom Gallows
When new people show up, Tom's not in the mood. He hasn't even memorized what he's got, for crying out loud. He summons the gargantuan fire beetle immediately. Then he starts apologizing, "Well, perhaps that was the wrong thing to do, I mean, they might be quiet types. Sorry 'bout that, are you okay? Oh, I'm sorry about the burning there, that looked like it hurt, oh nice shot to its eye! etc."
(it should be noted here that the skin does not record anything TOM says)
Unfortunately, the adventurers will likely say something after the beetle is dead, and if it's not clever, Tom will respond by calling upon the water portal to flood everything, washing them away. Or rather, that's what he hopes will happen.
In truth, the water will tend to flow into the slightly lower dwarven mines instead, flooding them and putting the PCs back on solid ground.
One possible clever response, which might elicit his cooperation:
"What's that on your skin?" "Here, let us write that down for you"
If the party manages to get Tom Gallows to be friendly (by recording his skin onto a proper diary, so he can read it later), he can be very useful. He knows Mud's story, and how to destroy him; he knows how to use two of the portals, and knows a few riddles that might indicate the commands for the other two; he knows where Gruenwick kept the keys to his treasure chests.
Hooks
Hook #1: Simple. The heroes are hired to finish the job of killing the undead. The dwarves will pass on what they know, and send them in. The cave pony is still around, hoping for some way to recover its master, and someone with the ability to speak with animals will get most of the story (along with plenty of "bloody stupid beetles" mixed in).
Hook #2: The drow know Mud's story. They think it's funny as heck. So they told a few duergar buddies over a few drinks, modifying it a bit for audience, who passed it on to a few others. Somewhere down the line, some duergar told some dwarf, and it spread from there. Of course, the tale has changed in the telling, and now it's 'known' that there is an intelligent Dancing Sword floating the halls of an underground tower, and any who knows its name (Mud or Muck or something) can free it, or perhaps it was command it. The bard PC hears the story, hears about the dwarves uncovering some underground tower, and puts the two together.
Hook #3: There are four portals in Gruenwick's lair, and the tower's pretty nice to boot. A party wizard or necromancer could easily find a reference somewhere to them, and decide that the place would make a good second home and teleport haven for those overwhelming combats. Sure, it's a fixer-upper, but you just can't beat a place so off the beaten path, eh?
Hook #4: Janna's church commands it. Pick an appropriately heavy handed God of Good, and crack the whip a bit.
Hook #5: If it's good enough for ole Tom Gallows, it's good enough for me. The next time you run the PCs through a drow module, and they're fleeing the drow, have them stumble down some dead caves that look like a good hiding spot. And heck, even when a few undead show up, they're not as nasty as the drow. Explore the tower a bit, rest up a bit... and meet Tom Gallows, the last person to stumble on these halls.
Loose Ends
Because there's a lot of them.
Tom Gallows: He regenerates, ignores 15 points of elemental damage, breathes water, etc. He can't attack, but he can be very annoying. If someone unstaples him, he will say "Thank you" and die. If he's left there, well, that's a DM's job, making horrible over-arching villains from threads the PCs leave behind.
The Tower & Portals: If the PCs don't use these, but they do clear out the defenders, the dwarves or the drow will end up with them. This could influence politics in the underdark.
The Drow: If the PCs were running from the drow, and then leave into the dwarven caves, this is an excellent opportunity to warn the dwarves about the nearby drow. Or not.
Mud: If he's freed, there is now a blackguard loose. If he's not freed, there's still a really malevolent sword out there.
. If I can keep it up without imploding 
.
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