Dark Sun: The Builder's Cry
So I've been a bit lax on writing things up for a bit, but that's because I wanted to leave this until my PCs had advanced a bit further into the game. This means I can give a good explanation of what I'm trying to accomplish in this adventure and how I am wanting to design all of my DnD games going forward.
At the end of last session, the PCs had discovered there was a homicidal group of thri-kreen at the ruined city, that the elves weren't the bad guys, a group of broken builder cultists had infiltrated the caravan and that something sinister was going on here. Coming back to the caravan, rumors flew about as to the disappearance of the Nibenay inix with much of their precious metal weaponry. Thankfully for the PCs, the Thri-Kreen they killed were rapidly blamed for the heist and while some remembered seeing some Gulgian soldiers wander off - the PCs were not directly suspected.
The caravan made fast progress at this point, without much harassment from monsters and other hazards. In reality I wanted to get the game going and the PCs circumvention of the "order of things", notably by killing the ssurrans leader meant I didn't want to use the prepared encounters with them. It would feel more than a bit unfair to the players if their decision didn't have a major benefit, so they got through relatively unmolested until they ran into a group of nomadic desert merchants. Now if you recall, the PCs got themselves a host of metal weapons, many of which they won't actually be able to use fully anyway.
Aside from being a place to buy and sell equipment before something terrible happens - let's face it, I've been hinting for a long time this city is particularly nasty stuff - I wanted the PCs to acquire items that would help them. The first and most important one was the mace of disruption. Now nobody in the party uses maces much and the assassin is focused on light blades, but I wanted to temp them with this item. Firstly, it really does a lot of damage to undead and gives the party a valuable radiant option. The second was to give a very strong hint to the PCs they were going to be walking into undead central.
Mace of Disruption +2
This ancient weapon made from some unknown creatures bone is inscribed with strange writing and glows brightly with radiant energy.Enhancement: +2 attack rolls and damage rolls<br>
Critical: +2d10 radiant damage<br>
Property: Undead struck by this weapon gain vulnerable 5 all until the end of your next turn.<br>
Property: Whenever an undead creature is destroyed within 5 squares, you gain temporary HP equal to the enhancement bonus of this weapon.
Property: This weapon does not break when used with reckless breakage, but its powers and properties cannot be used until after a short rest.
Power (Daily * Radiant): Free Action. Use this power when you hit an undead creature with this weapon. Deal +2d10 radiant damage.
This weapon basically gives some very firm bite against undead creatures. It also is what I consider a very effective "rare" weapon. It will eventually fall behind other options, but while it is useful it is *extremely* useful. At the same time, as this game uses fixed enhancement bonuses it will hopefully remain quite handy for some time. Importantly, the radiant damage interacts with undead creatures in important ways - such as denying wraiths insubstantial and preventing certain other enemies from teleporting (as examples).
As well as the mace, the PCs also had access to a power jewel - an item that lets them get back a single level 1-3 encounter power. As I alluded to above, the merchant wasn't going to just trade these things for ceramic - he wanted metal. After some negotiation, the PCs took both the mace and the power jewel. The player of the executioner even riggered his character a bit to use the mace of disruption (over his usual metal rapier). That was good to see, because I wanted that item to be extremely tempting - even if it wasn't something any character was directly using.
And thus did they advance to the risen city, oblivious to the true danger that awaited them. At this point it's worth discussing what the initial part of the adventure is meant to do. The risen city was destroyed in a terrible cataclysm, which either annihilated its population or warped them into terrible monsters. For reasons that the PCs don't know yet, the city "sunk" underneath the sands and was wiped from the history of Athas (as such, it is not named specifically quite deliberately). Now that it is back, the true terror of the place is now known: It's former population are a huge horde of ravenous undead creatures. Each night they rise from the sands and swarm over anything foolish enough to be within the city.
This "feature" has several points: The first is to make the approach of night absolutely terrifying. As the PCs explore the city, they must keep an eye on the relentless sun. Should they be caught in the open at nightfall, they will be surrounded by a terrible horde of ever increasing undead. This means they need to consider finding shelter before night falls and explore the surface during the day. It also means they can face different encounters and creatures depending on the time of day. As an example, one tomb may be filled with sunwarped abominations and other creatures during the night, but by day they leave to wander the surface abandoning the tomb (and making it safer to explore).
The second point was to dramatically destroy the caravan, showing just how rapidly the undead could overwhelm even the strongest force. This meant the PCs "safety" line is cut off and heightens the terror/drama of the situation. Now survival days mattered and depending on their actions on the way to the caravan: Groups of survivors appear around the city. Some of whom can be valuable allies! Additionally, by showing how trivially the undead horde swept away the caravan, it shows the PCs they do NOT want to take on the undead.
Of course it is important to show this concept to the PCs and the first encounter of the city does exactly that. Surround the PCs with a non-stop stream of ever rising undead abominations - while they can clearly see the massacre around them.

As night falls, the PCs camp is broken by the presence of numerous undead...
Initially the PCs treated this as any other encounter, grouping up a bit and trying to fight off the undead. But after a few rounds and the undead horde ever expanding, it soon became clear the situation was hopeless.

Increasingly, the undead were able to get closer and closer - surrounding the PCs. Bob in particular was caught out, due to his large size and the numerous undead hoarding him. Due to his low level, he was hit by pretty much everything and rapidly lost HP...
A fighting retreat became the only option, even as Bob was torn to pieces by the undead and fell amongst them - shrieking as he did so. With their blood lust not yet sated, the creatures pursued the PCs to the nearest available structure: A tomb half buried within the sands.

Bob falls to the undead horde as the PCs escape off the map to flee to a nearby tomb...
As they fled the rising horde, they found the tomb was warded and secured with thick stone doors. The doors and wards were extremely ancient, seemingly to keep things *in* instead of letting things out. None the less, some fiddling with the runes allowed the PCs entry. However this was not in itself guaranteed protection as the undead horde were soon tearing at the doors and would beat their way in given time. The PCs then fled deeper into the tomb, keeping ahead of the horde behind them and facing whatever challenges were in front of them.
I felt this was a great idea and worked out brilliantly. The PCs did not relax until they got much deeper into the tomb and even then, the horde was an ever present threat upon their minds. It also provided great impetus to get further in and quickly - because should the PCs be caught between two encounters it could have been devastating. It is worth noting that the horde is utterly unrelenting: Once they get an idea living flesh is somewhere, they go after it until they have destroyed anything alive. I like to think of them as one gigantic infinite monster, that expands and expands as you fight it - a genuine legion. More of an environmental hazard than a group of monsters and with a very similar purpose (game wise).
Eventually the PCs came to a strange room with a massive gaping face in the ceiling and a pool of water within the center. Unfortunately, the undead guardians of this room were none too happy to see these living intruders!

The zombies here actually do more damage on charging, something the PCs discovered to their horror. Burning skeletons threw fire at the PCs and the sinister shadows revealed themselves. Suffice to say, I now have my third group of players who utterly hate shadows.
This encounter was generally handled okay, except that Alek got himself in a position where I could really have a go at him. It's worth noting that most creatures have a simple tactic: Kill the leader first, then whoever else gets in the way. The lack of caution meant the PCs needed to desperately salvage the situation for a while. It's worth noting that once up, the Ardents immensely deep healing resources quickly get everyone back on track.

Alek got a big ouch here and the executioner had to pull him out...

With the situation restored the undead quickly fell to the PCs blades. But at a terrible cost!
With the fall of the last undead abomination, the PCs relaxed and began to move north towards the door... when there was the slightest of clicks and suddenly... A TRAP!
Now traps are a wonderful thing and allow me to take some time to explain why, even if they are a pain in the ass to design you should use traps. The first good reason is that they really break up combat and present a different challenge. For the most part, you can't attack or affect traps with powers. So this changes the tactics the PCs need to use. The second thing is that there is a puzzle element to traps that I enjoy and like inserting to them. In this case it was fairly obvious: the doors come down and the room fills with water. If the PCs force open the grate in the pool of water in the center of the room (you can see it above in the maps), they can reduce the flow. The doors are the obvious targets, so before they could be opened (unless bashed down) I put some lightning gems on them just to spice thing up. Nothing is better than water and lightning!
The second good reason for using traps is the paranoia they cause. PCs will need to advance slower and be more careful where they step. This isn't to say you should over use them, but mixing them in commonly with combat encounters - but not every one - can make life very interesting. Also bear in mind that traps are again, not something you can easily affect with powers and so provide a very different kind of challenge.

....*click*... oh oh...
In this case, the face in the ceiling opens up and spews forth water into the room. Magic doors slam down and seal off the room while it begins to flood with water. I chose this trap for a few reasons:
1) The irony of being drowned on Athas was not to be underestimated.
2) It was more of a skill challenge than anything else, though I did also put some undead on the other side of the door (in case the PCs noticed the pressure plate on the floor and jumped over).
3) The trap is actually quite useful if the PCs don't entirely disarm it (remember they are being chased by a horde of undead trying to beat their way into the tomb from the other side)
4) Water in this module is an extremely important resource - as it provides a bonus when you rest (explain more later!).
The trap in the end managed to swirl some PCs around and fry a few with lightning, but otherwise was negotiated well. They quickly cottoned onto opening the grate to slow the water, so it wasn't quite as dangerous as it could have been in the end. The first time I used this kind of trap BTW, I also included sharks. I think the sharks make it really exciting to be frank. In hindsight, sharks are quite an essential part of this trap that was missing here. So note that down: Water Traps + Sharks = really great. Just water trap = Great, but is missing sharks.
In any event, after disarming the trap the undead on the other side were none to happy about them either. I sometimes wonder if my PCs enter every room wondering "Will we be greeted by something that IS happy to see us?". Minding when they do find something that is happy to see them, it's probably because it was very hungry and the PCs were a convenient snack that walked right into its midst.

These undead were a blockade here. The purpose of them wasn't to be a "real" encounter, but instead make the threat of the trap still an issue by blocking the doorway. If the PCs perception found the pressure plate, they could just jump over and avoid it. Hence these seemingly random undead. It's worth noting that the monk put a quick end to the corruption corpse. Turns out a stone to the head IS mightier than the biggest fullblade!
One thing I think my PCs really enjoyed was the critical effect on the zombie undead. Basically, if they get crit they die instantly and many special effects (like death attacks) don't work either. The monks sling to the head was invaluable, taking out the corruption corpse and its powerful -5 attack aura. This mechanic though I really like and it works very well in practice, plus it happily unifies all the different zombies together mechanically.
The PCs handled them pretty easily in general, but bear in mind they are there for a specific purpose: To hold the PCs near that corridor and possibly activate the trap. Ironically, I think by activating the trap independently of drawing the undead creatures attention probably is the easier way of doing this.

The undead held the corridor for a while, but ultimately were swept aside. This is a pretty classic corridor fight as well, not something I've had in 4E for a while.
The pressure of the horde behind them kept them going, even with the leader on 1 surge and they soon entered into another large chamber. This chamber had a huge ornate sarcophagus in the middle and seemed considerably damaged. Like elsewhere, the undead inhabitants were not happy about the PCs entering and soon attacked.

I wonder what is in the sarcophagus and OH DEAR GOD IT'S A MUMMY!
My PCs didn't need any incentive to hate wraiths (who does?), but the mace came in handy immediately by giving the wraith vulnerability and removing its insubstantial. Unfortunately they couldn't fully capitalize due to the wraith being quite tricky and teleporting away (curse you wraiths, you win this time!). I must say that the wraiths ability to appear almost anywhere due to their teleporting ability makes players extremely paranoid. Half of one turn was focused entirely on where the wraith ended up disappearing to.
Oh and on the second turn I made things REALLY interesting by pulling out a mummy - who burst forth out of the sarcophagus. What undead desert adventure in a tomb couldn't use a mummy? I mean come on now. This was also an opportunity to see how the new MV mummies went. This guy is interesting because they have a curse that doesn't end (until the mummy is destroyed) and because when they first appear they can stun an enemy that sees them (the battlemind was the unfortunate victim of this). With a reasonably hard hitting main attack, mummies are a pretty neat monster and I will look forward to using them again!

Note that I hid the wounded wraith in the corridor (originally behind the tiefling mage. The PCs expected the wraith to be next to the leader, but I like to be surprising.
Once the wraiths were dealt with, the PCs were able to take care of things reasonably safely and destroyed the remaining undead.

The wraith came back to attempt to kill the leader - it was a last ditch attempt I must admit by this point.
It's worth noting that the executioner is the best class in the game to have against insubstantial undead. Due to death attack, which kills any enemy under X HP (10 in heroic) they are very efficient at killing insubstantial creatures like wraiths and (previously) shadows. Due to halving damage, insubstantial creatures are masters of lurking around on 1-5 HP. Not so with an executioner, who will guarantee killing them below 10 HP.
After dealing with the wraiths the PCs got another important item:
Moonsilver Staff +2
Critical: +2d6 radiant damageProperty: Treat this staff as silvered (Player’s Handbook, page 220) for the purpose of implement and weapon attack powers made using it.
Property (Encounter): Free action. Trigger: You use an arcane power with this staff. All damage that the power inflicts is radiant damage, replacing any other damage types it would have previously done.
Power (Daily): Free Action. Trigger: You hit an enemy with an arcane power and deal damage to it using this staff. Effect: That enemy takes 7 extra radiant damage.
This gives the wizard a radiant option, again t help the PCs with undead but still keeping important tactical choices (you can see where I am going with these items). You'll note that the damage both the mace and this staff do isn't always radiant. I want - for the most part - the PCs to make difficult decisions as to what enemies to hit with their radiant powers. Especially as radiant damage isn't exactly easy for this party to get at-will.
At this point the PCs met a strange spirit, who unlike his fellow seems to have some of his mental faculties intact. The spirit explained that the city was destroyed in a great cataclysm and buried beneath the sands. He suspects the cities sorcerer-king Dralnu must have something to do with it. Unfortunately if the PCs wish to deal with Dralnu, they must somehow enter his inner sanctum. This is not an easy task, as it is warded using the life-force of his three most powerful templar: Ulyoth, Xelno'taph and Chattur'gha*. The PCs will have to find them and either kill them, or persuade them to aid the characters in opening the wards to confront Dralnu.
All the while other events within the city move forward....
Before ending this (really long) post though, it's worth discussing resting. Like in my other game Dark Prophecy, I've chosen to affect resting differently depending on where they do so. Resting during the day on the surface is actually the safest, but costs the players a surge penalty (due to resting in the sun) and is cumulative. Resting underground is neutral, without a penalty or bonus. Now I mentioned above that water is very important and it is for another reason. Resting where the PCs have easy access to water doesn't require using a survival day, but best of all it gives a +1 bonus to surges per day! So resting around water is *very* handy! This means locations where fresh water is are very valuable and well worth looking for.
Next week, the map of the city and making important decisions...
*Yes, this is totally an Eternal Darkness reference and unashamedly so. It's an awesome game and if you can find it, buy it, buy a Wii (or a gamecube) and play it. Highly recommended.