Tangent time.
(a) Somethings Should Not Be A tribe of kobolds that worship Shub-Niggurath are picking off outlying farmers and their families for appropriate sacrifices by stealth, trickery and guile. They leave booby traps behind to thwart nosy neighbors picking up their trail. The kobolds' goal is to "seed" several Dark Young in their turf to wipe out the annoying human settlements.
Depending on the APL, they're going to hopefully thwart the ritual before it is concluded, or they're going to tangle with one or more Dark Young. Best way to run something like this is to establish a timeline, during which other more mundane events are occurring. Let's see how well the players pay attention.
Are the PCs up to the task, or will a thing out of nightmare rampage through the budding kingdom?
(b) Winter is Coming or has Just Arrived. Go all Game of Thrones if you like with certain death encroaching by way of a horde of spawn-inducing frozen undead horrors, or keep it simpler. Especially for groups that lack access to plot-thwarting magic, a massive prolonged blizzard entrapping them in a creepy castle during the winter holidays is prime fodder for setting up a gaggle of "small stories" all interlocking. It snows and snows and snows, dropping a dozen feet of snow during the course of a few days. Combine The Shining, Clue, Castle Ravenloft and The Thing.
Using this for higher level groups it's not a matter of the weather so much as it is a matter of how many important NPCs they can keep alive and well until the weather breaks. If the characters have access to weather control spells, perhaps a particularly nasty creature is able to counter their magic with its own. A hag coven, wendigo or just a yet-to-be-revealed BBET has decided to test the capabilities of his/her/its potential foes with lesser, disposable minions. One may (or may not) possess information that gives the heroes their first clue to the lurking threat.
Will the PCs be able to save the lords and principle players of the realm, or will these persons be murdered by rivals and/or picked off by a hidden horror?
(c) Dead Reckoning An organization of bored gnomes with low moral standards, strong clannish bonds, the Fell Magic racial trait and a surplus of ambition have decided that it's time to take over for themselves. They're fond of Necromancy and during the course of Other Events have quietly been amassing an army of armored and armed zombies (variants as the NPCs are capable of, although brain-eating zombies are recommended). Perhaps these charming chaps are the gnomes that have traditionally taken care of funeral arrangements, wakes and holiday ball/party planning.
Current events have taken a toll on the trained guards et al - i.e., all of the NPCs with respectable armor and weapons training with those that knew how to handle siege engines being particularly prized. Once they feel that they have enough of a force, they stage a coup of their own. A dozen or so 3rd level clerics or 4th level oracles with lesser animate dead can field a force of at least 100-200 zombie shock troopers with skeleton archers providing ranged firepower. An extended clan of 30-50 could directly command a much larger force, especially with access to Command Undead (feat) and command undead spells. Liberal use of desecrate and a choice voidstick makes this a nasty adventure for a lower-level group to contend with. The gnomes don't know the true power of a voidstick, or they'd be bending all of their resources to acquiring a great many of them.
Will the adventurers twig to any discrepancies as Clan Fellgnome prepares its master stroke, or will a horde of brain-eating undead pour into the Holiday Ball with indiscriminate hunger?
(d) Running Amok A supposedly simple premise: a powerful demon able to possess others gets it in its head that the local orphanage or school house is a prime source of entertainment. Not by endangering the children or bringing them to harm ... oh no. By using the urchins as the hands that its skills bring to bear. Sabotage, poisonings, sneaking in to acquire blackmail materials, starting up stampedes, many things are possible.
Can the heroes determine what is going on and stop the fiend before it unleashes a fire in the crops shortly before harvest time? If it succeeds in doing so before they track it down and stop it, how will they handle the potential famine?
