I apologise in advance for the length of this. I hope I've made it interesting reading, but the fact that I'm doing a modern setting, and the ambitious nature of the scenario, pretty much guaranteed that I was going to have a 4K word count.
St Margaret's Tear
Femme fatale - the female PC/NPC and the egg
Crumbling temple - used to make the PCs think the egg is a good thing (dragon ley lines, etc.)
Origami golem - a paper tiger, and I apologize for it 
Pearl - a false pearl, at that, with the usual evil that that implies in literature
Forboding mansion - a mansion that forbodes
Ex-monk - his name is Pitr Vascova
Note: a forbidding mansion would be one that seemed like a bad idea to approach; a forboding mansion is one that provides foreshadowing of something awful, but could itself be quite pleasant. The essence of a femme fatale is not that she is both female and deadly, but that it is her very femminity that makes her deadly (typically by seduction, but I varied it a bit herein). And I am using the ex-monk in the literal sense, rather than in the game system sense - he has left his monastery and abandoned his vows.
Usually, the scenarios built for IronDM are plug-ins... short encounters that can be dropped into a pre-existing campaign for extra spice. What I am trying for here is vaguely ambitious, however - it is an introduction to a new campaign, in a not-entirely-generic setting. Worse, while it can be adapted for fantasy with a few tweaks, it is designed with the modern world in mind.
The upshot of this is that this scenario is a pre-fab construction set. A lot of the stuff in here can be tailored to your party's needs, and the actual way the scenario can go is up in the air. I try to provide guidance, but most of the real stuff is in the setup of a situation that can blow up for everyone's amusement.
Setting Notes: Earth, 199x. It's the world you knew, except that there are terrible secrets about magic and monsters, concealed by our willing ignorance. The characters are those rare souls who choose, for whatever reason, to pierce that veil and live in the far scarier world of the truth. You can run this from a Cthulu stance (everyone dies or goes mad or fails horribly), an X-Files stance (truth will triumph if you remain strong), or a White Wolf stance (you live in a strange world, and can make small changes, but the fundamental division between mundane and esoteric is never bridged). This scenario works with any of them.
There are a few factions of the supernatural explored in the scenario, and you can add as many others as you want to the campaign. The ones explored herein are the Illithid Vampires, a Dragon Cult within the Church, and an Order of martial artists who meet on the astral plane.
Characters (D&D): This scenario assumes no or low-level spell-casting. The characters are not yet familiar with the existence of magic, or have only JUST discovered it. Combat-worthy levels without spell-casting (fighter or rogue, for example) are fine. The purpose of the scenario is to draw them into the world of magic, and provide them with information - if they are already there, they don't need this scenario.
In addition to the normal needs for a party,
at least one character (PC or NPC) needs to be female. If a PC, the players needs to be prepared for some challenges - if not, you may wish to have an NPC female on hand as well. This character will be the one chosen by the Siren's Pearl as its host (it specifically needs a female if it is to produce children).
Some special optional rules to spice up a party caster:
Cleric 1 or 2: A holy person, likely to become a saint, who can sometimes manage miracles. Use the sorcerer's Known Spells chart (but from the cleric's lists) to determine how many Miracles the holy person knows how to Invoke, plus the Domain spells. Clerics can cast spontaneously here, but it takes a great deal of research, meditation, and prayer to master the Invocation of new miracles. For purposes of this scenario, a Church individual would be best.
Wizard 1 or 2: An apprentice to the Golden Dawn who is connected to the Church faith in some way, and has recently (oh so recently!) come across forbidden texts showing ways to swiftly and easily master magic... it comes at a cost, however, as the magic pries at one's humanity. Wizards lose -1 of (their choice) WIS or CHA for every five levels of spells they learn, rounded up. Thus, knowing 4 level-1 spells and a level-2 spell would cost -2 total. In addition, each time a wizard goes up in level, he may choose to lower one of WIS or CHA by -1, and RAISE his INT by +1. Loss of wisdom results in being ever more cold and logical, losing the ability to
understand emotion or others' behavior; loss of charisma results in a slow decline into psychopathy, losing the ability to
interact with others in a meaningful fashion. Neither can be reduced below 1, and when they both reach 1, the wizard can learn at no cost (but can no longer improve INT each level).
FACTIONS
The Dragon Cult: Dragons once roamed the earth, and never will again... but don't tell that to these folks. They have studied the ley lines of the Earth for centuries, ever since a young monk in Feudal Italy stumbled across the study of wizardry, and realized that ley lines were the shattered remnants of dragon spirits.
In the centuries since then, they have always moved to acquire or build monasteries at key junction points, using the architecture to direct and store the magical energies there, and then gotten the buildings abandoned by the Church. There are not many - few enough to count on two hands - but each one has established a powerful link to the past. Their goal is to return dragons to the world by building a vast network of these monasteries and then reconnecting them at an astrologically auspicious time.
And although the monasteries are abandoned, the faithful of the Dragon Cult often live among the crumbling ruins, maintaining the pools of energy there and guarding their investment.
One such monk used to be Pitr Vascova, detailed in the NPC section, and one such monastery was the Tear of St Margaret Monastery, some ways outside of Moscow.
Saint Margaret and her link to dragons
The Tear for which the monastery is named is a fist sized pearl... except that its resemblance to a pearl is only in its luminous coloration. It is more like petrified egg white, and is believed by the Dragon Cult to be exactly that - a dragon's egg.
St Margaret's Tear: In fact, it is not petrified - that is its natural state. Nor is it the egg of a dragon, but rather of an
illithid, an alien species from a distant interstellar empire. They burned out of existence several million years ago, having genocided the multitude of sentient species that kept them fed. Having learned their lesson, but still unable to escape their inevitable racial death, they sent eggs to planets they thought might develop sufficiently complex life for sentience to arise.
The egg requires a powerful mind to keep it nearby for some time in order to develop. For millenia, it has been passed back and forth between the weak minded, however, until it came across the Dragon Cult... although naught but a babe in illithid terms, it is cunning and intelligent, and possesses rudimentary telepathy, which it used to get itself placed at the monastery, in the hopes that one of the cultists would become sufficiently powerful to facilitate its birth.
Unfortunately, it was a bit too clever in getting them to see it as an object of worship. It has been locked behind glass for nearly two centuries now.
Its eventual goal is to find a powerful wizard and be birthed (it is a psychic entity, rather than a physical one) into the body of a highly intelligent female, so that it can birth more of its kind and begin a program to infest the sentient species of Earth.
When its species achieves critical mass, it will begin enslaving the human race and recreating its former interstellar empire (with enlightened, modern laws regarding the overeating of sentient herds).
The Silver Chain: An international order of martial artists who have, in their inner search, discovered the astral plane and consequently been invited in. Their primary goals are self-enlightenment and secrecy, but they occasionally do good deeds as well. The intense psychic training possible in the astral plane has reflected in the physical world as well, and they are typically psion/monks or psychic warrior/monks.
Silver Cord (general feat): You have learned to astrally project. However, the astral plane is a pretty dangerous place, dealing d4 temporary INT damage every full minute you remain in it unprotected. You can see & hear into the physical world as if using clairvoyance/clairaudience (by locale). There is no time limit, other than the psychic damage.
Silver Chain (general feat): Prereq WIS 13+, Silver Cord. You have created a demiplane for yourself. In general, a demiplane has no special abilities unless you develop them separately from this feat, but you can work with your GM to make it interesting.
Due to some influence from St Margaret's Tear, some among their number have become convinced that the artifact hidden somewhere in the monastery is the key to Ultimate Martial Power... unfortunately, knowing where it is astrally is not the same thing at all as knowing how to get to it in the physical world, and this has spanned a years-long search for the monastery the egg is hidden in.
And they are much better fighters than detectives.
NPCS
Pitr Vascova: A former member of the Dragon Cult and a former monk of the Church, Pitr fled and abandoned his vows when dark dreams drove him nearly mad. They started when he first moved to the Tear of St Margaret, and he has had an unhealthy obsession with that monastery (from a distance) ever since.
Once a sensitive artist who was fascinated by dragons (and entered monastic life to be part of the Dragon Cult movement), he lived a quiet life of contemplation, painting and sculpting his favored subjects (themed around Saints, of course), and
believing in the eventual return of dragons to the world. He'd also mastered some of the ley line magics that connected him with dragons (1 or 2 levels of sorcerer, nothing compared to what the devoted cultists can do).
When he moved to the Tear monastery, however, things began to change. He dreamt of worms moving through his mind, and of a dragon, dying and tortured by the same worms. He dreamt of a foul-looking squid on the head of a woman, scooping the skull of a monk while blood dried on the walls. Worse, the dreams hinted at darker things... and he began to believe that the Dragon Egg was one of the worms in his dreams, and that it was trying to get inside him (it was).
He broke after less than a month of the nightmares, and fled the monastery to begin a new life of binge drinking and obsessive research. Looking at records of the Tear in a new light, he began to realize what it wasn't... and it wasn't the noble dragon of his fantasies, but something else.
Melpomine's Keeper: This is a singular individual who also has a demi-plane in the astral realm. His demiplane is built around a bound Muse (treat as a 1/2 celestial dryad, nymph, or similar) who provides him with insight, creativity and similar things.
He is not a nice person.
He has also discovered the egg, and seeks its location. He's a better researcher than the Silver Chain, however, and though he started later, is likely to find it sooner.
His demiplane resembles a vast mansion (which the PCs will likely be taking for their own early in this scenario) with a variety of paintings throughout. Although few know it, the paintings show images from the possible future of the people viewing them. The coolest part of his astral demiplane, however, is that it allows people to approach in physical form (using a variant of
Mordenkainen's mansion combined with his astral feats).
He also has one other wonderful toy: a life-sized paper tiger that acts as his bodyguard in the physical realm (see Origami Golem, below).
Origami Golem: This is a golem made of thick, folded paper in the shape of a three-dimensional paper sculpture. It is usually constructed to resemble an animal, and has the same stats as that animal, in addition to its golem traits.
Golem Traits -
Weight changes to 50 lbs
HD changes to d10
Speed: Same, but can't run
Construct: Immune to mind-influencing effects, poison, disease, and similar effects. Not subject to critical hits, subdual damage, ability damage, energy drain, or death from massive damage.
Magic Immunity (Ex): Golems completely resist most magical and supernatural effects, except as follows. Fire-based attacks do damage normally. Force-based attacks cures 1 point of damage for each 3 points of damage it would otherwise deal.
The most significant aspect of an origami golem, however, is its portability. It can (as a full round action) contract to a 10 lb stack of paper or expand back out to its full size (where it weighs 50 lbs). The origami golem can be carried in a reasonably small briefcase, and weighs as much as an early 90s laptop when so compressed. This is important to Melpomine's Keeper, who has many enemies.
ACTION
Fortunately, most of the complexity is in the setup! If you have a good grasp of the factions, the rest of the scenario largely writes itself. I will, as a courtesy, show you how

.
Part I: Get the PCs to Moscow
This part's pretty easy. Use one of the hooks below, or make up your own, or just explain to the players that the fun stuff is in Moscow

. They don't need to know about the Tear yet (if they don't, it will lend more of a "what the hell do all these people want?" feel later), but if you want more of a straight adventure, it won't hurt if they do.
Some hooks:
The Church is investigating a possible internal cult and the PCs are working for them (as faithful agents, hired mercenaries, what have you), and there is some
strong evidence that the cult is based out of Moscow, and is armed and dangerous.
Pitr Vascova, in his fleeing travels, finds himself in a bar in the same country as the PCs. He tells them his tale. Depending on the PCs, you could play it up as (a) he asks them to help him destroy the Tear, (b) he's a drunk mumbling about an Ultimate Power Thingy in a Moscow monastery, (c) he's changed his mind and wants the Tear now (he doesn't tell them about the Tear) and hires them as bodyguards for his trip back to Moscow (he stole money when he fled).
If one of the PCs is a wizard, they could stumble across a reference to a Pearl of Power (not the normal D&D item) that allows a wizard to learn more spells than normal without WIS/CHA loss. It was last owned by a Russian czar, although it disappeared when the Church got him beheaded, and disappeared somewhere in Moscow. On-site research is needed to determine its location...
Really, though, there's a bajillion ways to get the PCs into this. Any kind of PCs, any kind of overall campaign - just pick an NPC or group that they're compatible with, fiat that the group has discovered something about the Tear, and have them hire, plead, blackmail, wheedle or entice the PCs to get it for them. That's the great thing about powerful artifacts.
Part II: Finding the Tear of St Margaret Monastery
Regardless of how they get to Moscow, the trail leads to a monastery well outside of Moscow. If they're looking for THE Tear, they'll find some good books about its history in the Moscow libraries; if they're just looking for A Tear (without any idea of what it is), they could stumble across someone who saw the exhibit. If Pitr's with them, he'll know the way, and if they're working for the Church, they can find a manifest that indicates the cult uses the crumblinf, old monastery is a possible base of operations (perhaps the manifest lists the address).
Whatever clues they find, however, there will be a diversion before they can go there.
If it's late at night when they get the facts, and they decide to go there in the morning, you can have Melpomine's Keeper interrupt their sleep and ask to speak with them. He is a heavyset man, with a very ordinary (
alter self) face. Otherwise, they can just run into him... but the goal is for him to NOT be very likeable, and interrupting their sleep will help with that.
Regardless, he will ask them (agressively if need be) why they are looking into the monastery. He will be brusque, discourteous, and won't answer questions in return. He will warn them off, or offer to hire them if they will bring the Tear to him. Remember: make them dislike him!
The purpose of this is some DM subterfuge - while they're busy deciding he's the BBEG, the Tear will be moving slowly into their possession and into the hands of the party spell caster. When they defeat him, they should be planting the seeds of their destruction. Melpomine's Keeper is merely a red herring...
At any rate, they should say no, or if they say yes, he'll screw them. Either way, they will eventually need to fight him to get the Tear, and that should be set up here and now. If they try to fight him NOW, of course, the origami golem will cover his escape, and then blow away into paper (you can give him more than one, if the PCs seem adept at taking them apart, or he has to abandon it).
Part III: Investigating the Tear
Once at the monastery, a few things will happen.
1) The Dragon Cult will become aware of the PCs' interest in the Tear. This is not something they like, and they will begin surreptitiously following the PCs. The PCs may be aware of someone following them, but the cultists will flee confrontation - most of them are like Pitr, sensitive souls who believe in dragons, although they ARE sorcerers.
2) The Silver Chain order, who have managed to find their way to Moscow, but not much past it, had a lucky coincidence - they overheard the PCs figuring it out. One of them is surreptitiously following the PCs to find out what other goodies they can figure out, while the others plan their night time raid.
3) The PCs will see the Tear. And the Tear will see
them. Specifically, it will spot the intelligent female PC or NPC you made sure was in the group (in the characters section). This, it will decide, is its perfect choice to bear its infantile mind and be the mother to its species... and it will do something it hasn't dared to do in centuries. It will telepathically speak to its target. Adopting a voice not unlike what you might imagine from a baby dragon, it will plead for help in escaping its captors. It will offer to teach magic in return, and merely ask for freedom from the arcane torture it has been subjected to. It will explain that wizards drain their own madness into it, causing it immense pain - the magic it teaches does not cause or require this. Please?
Part IV: Stuff Happens
No, really

.
There are plenty of conflicts and alliances possible, and they all lead where the game needs to go. They could end up discovering the Silver Chain and fighting with them over the Tear... or talking with them and allying with them to protect the Tear.
If they actually have a chance to speak with the Cultists, and tell them what the Tear said, the cultists may even PAY the PCs to take it and protect it. Otherwise, a cult of low level sorcerers can provide a pretty serious fight.
Other factions could be introduced, with similar wishy-washy ally/fight results. It depends on who the PCs get along with.
They won't get along with Melpomine's Keeper, of course... if they let him hire them, he'll happily take the Tear, and then betray them to the Dragon Cult so he doesn't have to meet any of his promises to them. If they didn't hire on with him, he'll just steal it during the confusion of dealing with everyone else.
In the later case, his plan is to leave a false Tear in its place (an unusually large true pearl), and he would probably get away with it... except that the pearl is silent, and the female character knows its not the same.
Part V: If This Was A Five Act Play, You'd Be Killing Something
The big fight with Melpomine's Keeper. He's a wizard with one or more origami golems, hiding on his home turf in the astral. He should be tough, but scaled to the party, and eventually they should be able to kill him... and discover that they've inherited some really nice astral property.
The place will indulge them in terms of layout, be defensible... and offer quick retreats and clairvoyant capabilities.
They'll also have the Tear, and generally, anyone who they're allied with will agree that they're the best people to protect it (because of the female character that it is fond of), and everyone else is likely to be an enemy.
The paintings in the mansion are the only sore point. Images of worms crawling through skulls, strange alien humanoids with tentacles coming out of their open mouths, and any other forboding images you want to steal from future plots you're planning. By the time they figure out that the pictures are
precognitive, you can have them discover and free the Muse causing them.
The Muse has her own painting, too, the one she's trapped in. But that's another scenario...
Future Lines
The female character should start out reasonably nice or heroic, or whatever passes for it in the group. As time passes, she should become more cold and vicious, more willing to shed blood to achieve the aims of the group. And the Tear will be teaching her magic, even as her form begins to alter.
Eventually, she will need to learn spells to conceal her changes (possibly a 3rd level Alter Self that lasts for 1 hr/lvl?), as she will be becoming an illithid. This is why you need to pick the player carefully - she isn't failing saving throws, she's just merging with the psychic creature in the Tear.
Eventually, the party will have the opportunity to stop her, or NOT stop her (in which case she will disappear into the 6 billion population of Earth, finding new targets and implanting psychic eggs in them).
I mentioned the Cthulu, X-Files and White Wolf stances. Here's where they come in:
Cthulu: She's going to escape. You KNOW she's going to escape. And trying to find her will just lead you into a pit of despair, or yet another world-devouring monster. In fact, distract them with a world-devouring monster, and then, game years later, have them stumble across a secret Squid-Faced Bible titled something akin to Mein Kampf which explains their plan, but not how to find them. While you're at it, the Muse is actually a soul-devourer that possesses artists and inspires them beyond human limits until madness and death overtake them.
X-Files: If they don't stop her, the government will hire and equip them to find and stop her. It will be a long battle, but one they'll eventually win. And while they're at it, they'll prevent the Return of Dragons (by the Dragon Cult), discover some hidden conspiracy in the bowels of Melpomine's Keeper's mansion...
White Wolf: Maybe they stop her. Maybe they don't. But they kick a lot of a** while they're at it, and in the end, what's one more supernatural creature running the government? Have them discover other supernatural Orders, get in fights over better artifacts... After all, the squid-faced people from Mars may have arrived, but they're gonna have to stand in line for taking over the world. Welcome to Earth, b****.