Looking for inspiration, city investigation adventure

[Gez]

I've reached a DM's block there. I need some help organizing a little investigation adventure in a city; involving mysterious ritualistic murders and suicides.

The story so far:
A little group is on a quest to find, and then destroy, an evil artifact (an intelligent sword with an overbearing ego and a genocidal purpose). They found said artifact into an old, and odd demiplane that had a long history of being used and reshaped by various crackpot wizards to conduct confusing experiments. However, given the strong ego of the accursed item, and its standard artifact immunity to sundering attempts; they had to find a bearer that would be immune to mind-affecting effects.

To that end, they passed a deal with an ex-wizard. They borrowed his personal Shield Guardian (as well as one special pet, because the ex-wizard would not give them the control medallion). In exchange for this huge help, our heroes would have to do a small service for the ex-wizard.

See, there's a detail that needs to be introduced about him. He's a skeleton. He should have become a lich, but he wasn't powerful enough to turn into one all by his own. So, he asked good old Goat-Boy Orcus for a bit of help. Orcus agreed, in exchange for his shadow. (You may recognize this if you've played or mastered "The Wizard's Amulet".) However, what Orcus didn't bothered to say that, upon separating ex-wizard from his shadow, all the magical abilities would stay with teh shadow, not with the living corpse. That's why ex-wizard is an ex-wizard, by the way.

So, ex-wizard asked the adventurers to find, and destroy his shadow. He hopes that, this way, he'll be able to reclaim his stolen power (and the special pet and shield guardian will play a role in that).

Our glorious adventurers haven't bothered a lot about this story of an evil wizardish shadow roaming around doing Orcus' work. They have their own tedious quest to do before. Or so they think.

Anyway, after several adventures, which included negociating with a dragonne, getting ambushed frequently by arachnoid goblins popping out of the ground, getting one of their own eaten by an ogre-mage (tiny flavour point: IMC, while mere ogres merely eat mere flesh, ogre-mages also consume the soul of their meal. You can't resurrect someone eaten by an ogre-mage.), escaping a sinking ship during a storm, and searching for a gynosphinx druid; the PCs have arrived at a point where they need to enquire about unsettling tales of ritualistic murders and suicides in a nearby city.

The City:
A river port city, surrounded mostly by forest, this is a small city by DMG standard. Notable features includes bridges, a river, and an aqueduct with watermill-powered pumps (Archimedes Screw, actually) to raise the water to the duct. There's a war raging on, and the city is threatened by siege, but the battle front is still further north, so it's not an immediate concern.

Other than that, the city's a blank slate, not really detailed. The characters haven't arrived yet.

The Mystery:
Remember that story about a wizard's shadow? It's actually a Shadow Demon with the class abilities of a Fiend of Possession and of a Fiend of Blasphemy. (Rather down-powered, though.) And it is the beast responsible for the murders. It has created a small cabal, but will sometimes possess people and make them commit heinous acts before suiciding its "host". The ritualized murders are designed to steal the souls and direct them to the Abyss, regardless of where they should have gone "normally".

I've an idea of the finale -- preferrably in the crypt used as temple, with the fiend hopping from crazed cultist to crazed cultist, enjoying its temporary invulnerability while he's possessing someone, hopping to column or other furnitures to disconcert and surprise the heroes, while a fair number of mooks (like zombies) would bog down the shield guardian, which is a true killing machine.

But for all the enquiry part -- letting the PCs discover clues, meeting a few shady NPCs that will help or hinder them, and so on -- I don't know how to do that.

I've never DMed this kind of things before -- some investigations, yes, but not open-ended ones; rather like things with a house or two to search for clues. Here, there's a whole city in which they have no contact, and they need to find what's going on.

Any advice or suggestion?

For reference, the PCs are:
LG Paladin 7th, LG Fighter 6th/Ranger 1st, CN Wizard 5th/Rogue 1st/Ranger 1st. With them, they have a standard issue Shield Guardian, a LN Spotter (the special pet, follow link in sig to find out what it is), and a travelling gnome (NG Wizard 2nd) that accompanies them mostly because he goes in the same direction as them, not really a help for combat. He's not fully stated, he's more a DM's plot device than anything -- I use him to explain some stuff about the world to the player, since he's a learned scholar.

 

[Gez]

If I'm allowed a bump...

 

[Hand of Evil]

Timeline: build a number of events that happen day+N, day 1 the first murder, day 2 the second...repeat until the major event takes place or the pc figure it out. Also think what the impact would be for everyday that another murder takes place, pressure to get the job done mounts, meetings called, people yelling at the party, people getting angry, copycat crimes, general fear...

Clues: Build a simple yes/no flowchart, clue 1 found, yes or no, if no go to murder 2, if yes go to clue 2...

Sometimes it is better to work backwards.

NPC - think about them carefully, you may have some important information being given to the PCs, the watch captain, the cleric that performs last rights, the street cleaner that washed away the blood.

Now, watch CSI or read an old crime novel.

 

[Gilladian]

flowcharting is a really good idea. Also, you may be able to build in some contacts for the PCs in this city. Is there a temple for the paladin? Maybe he can discover that a fellow paladin-candidate of his from his boyhood has been posted to/moved to this city. That would give him an investigative "in".

Maybe the scholar knows some people in the city. He might have a fellow sage to introduce the PCs to. Someone he's never met, but has exchanged letters with could be interesting.

Your rogue PC should be encouraged to meet with the local guild/crime syndicate. Maybe they are terrified of being blamed for the crimes because in the past one of their less savory (ex?) members used tactics similar to these deaths (at least superficially) to intimidate/terrorise his victims. In this case, they might even approach the PC for help, if his skills are known to them.

Always give your PCs multiple ways to find any clue, and be prepared for them to develop completely wrong theories. You may sometimes have to have an NPC simply tell them that something is "obviously a wrong idea" somehow to get them off a red herring. Or just adapt the red herring into the plot. That frequently works, too.

Be prepared to do lots of thinking on your feet.

 

[Hand of Evil]

Oh, don't forget the power of rumors. There should be a number of market place stories about what is going on, some may have a bit of truth to them.

Also, pull bits of news from the news, house fires, drug deals, gossip...connect some to your plot.

 

[Gez]

Thanks for the advices.

 

[Turanil]

Some ideas off top of my head:

--Let the ranger track some of the possessed murderer to the crypt.

--Let the paladin sense evil in a place obviously empty of creatures. Evil comes from the shadow which observes the PCs (assessing if it could attack them). Let someone make a spot check to discover that a shadow on the ground is not natural (is not a cast shadow), then trying to investigate the shadow flees.

--All possessed victims who performed suicide have the same ghastly horrified face in death, so it's easy to recognize all who died from the same cause. Let the PCs find and use a scroll of Speak with Dead (or similar stuff) to use to interrogate some of the victims.

--Let the players make wild theories and use these to railroad them into the good direction. I mean: they think they have understood what's happeneing and where next to see, and adapt the adventure so it happens to be true, and like this bring them eventually to the crypt.

 

[Prince of Happiness]

One thing to really ratchet up the tension is that these problems are going on while the threat of war hangs heavily on the city. People will be very frightened, very jumpy, and tragedies begin to stack up as the nervous populace starts to lock down and strike out at "outsiders" and minorities. This would definitely raise the difficulty levels for "Gather Information" and "Diplomacy" checks. People are gonna get very nervous around strangers asking questions.

Another thing I've noticed for city adventures, it's advisable to make every locale stand out. One of things that's going for a good dungeon is that every room will be interesting and memorable. It's not just some in, it's The Smouldering Cauldron, where a mysterious cauldron boils and smokes, no source of heat, and no one sure as hell takes a drink from it! Those aren't just docks, there's rotting fish everywhere and sailors with glassy eyes watch you in their black lotus (opium, whatever) visions.