It might take more than one swallow to make a summer, he said from a city where it would take about eighty Fahrenheit degrees along with any number of migratory birds to make it summer right now. But it only takes one monster to make a mystery. That, at least, is the thesis, or among the theses at any rate, of Hideous Creatures (providentially forthcoming, and long before the swallows do). Given enough attention to the monster, you can put together a fully satisfying evening or two of Trail of Cthulhu play even if the adventure might look a little bald just laid out there on the page.
Thesis, meet example. I’m going to use a subset of the clues as printed (or mostly) from Hideous Creatures: Byakhee, and reproduced below if you’d like to follow along at home and didn’t pick up that fine release. I’ll work sort of backward from them to create a short but stark adventure. Each story element I establish grows out of the flavor detail in a clue.
Our villain is summoning a byakhee for foul doings, and the clues give us the witch-cult (History) and a last name (Müller, from the Oral History clue) so let’s go with a witch named Karin Müller. Are the Investigators in Alsace-Lorraine or is she on their turf? Either one works, but seeing as Germans just got bounced out of Alsace-Lorraine in 1918 let’s have our Teutonic witch scion move to America — with a load of valuable art to sell (Art History, Chemistry) to pay for her passage.
So she’s an art dealer and a witch. What’s her goal? Maybe it’s tied in with both: she wants to inspire the genius of madness in an area artist, Paul Kerenyi (Art History, Assess Honesty) and also consecrate a temple to Hastur (Archaeology, Languages, Library Use) so she can re-start the cult here in Chicago.
Now, by reversing the process we can feed the mystery right back out.
Müller sent a byakhee to inspire one artist — Sarah Jones — but it got out of hand and Jones died; this brings in the Investigators (Forensics). They see the thing’s prints (Evidence Collection) and the weird effect on the vegetation where it landed, somewhere near Müller’s house or temple site (Biology).
Müller also stole the variant Euclid she needed for the consecration (Library Use) from the University of Chicago library. This might also bring in the Investigators, if they’re Book-houndly types.
They find out about Jones’ connection to Müller via Interpersonal talk with Jones’ friends or family; researching Müller points us to Alsace-Lorraine. This might not be time to drop the History clue, but it can be a leveraged clue for when they suspect witchcraft or when more than one clue points Müller’s direction. Such as when they meet her and she’s wearing an amulet of the Pleaides (Cryptography, Occult). Or when they see the genuine Schongauer print for sale in her gallery (Chemistry) and know (Art History) that he too was from Alsace-Lorraine.
Observation with Flattery (or gossip with a different Interpersonal ability) tells them she’s cozying up to Paul Kerenyi now. If they follow her or Kerenyi they hear her whistle, smell juniper (Sense Trouble), and then see her byakhee snatch him up (Art History). They can see the frozen ground here, too (Biology). If they stay home, they’ll see the byakhee and think of the art another time and make the connection: you can always throw in a rival Müller wants to kill or another unfortunate artist for another byakhee encounter if need be.
Kerenyi comes staggering back crazy talking to the Investigators about winged monsters and begging for their help. He’s got a heck of a sunburn, too (Medicine). The next day, though, he’s feverishly creating art based on his experience and now claims it was all a dream (Assess Honesty). This might be when to drop the clue about the “earth diver” and its role in artistic inspiration (Theology). He’s got another date with Müller two nights from now or whenever suits the game’s pacing. If you think there’s more than one whistle, or a player really grooves on Geology, Müller gave Kerenyi a whistle and mead to try out on his own; the Investigators can get ahold of it that way.
If they take advantage of her date to toss Müller’s house they find her mead (Pharmacy), her temple-consecrating cornerstone (Languages), maybe Shrewsbury’s book (Theology), and a map to wherever her sacred Hastur stone is unless it’s just in her backyard.
But the site or her yard is full of not just byakhee spoor (Evidence Collection, Biology) but also stones and mirrors (Library Use)! Which one is the sacred stone? The one aligned with the Pleiades of course (Astronomy)! If they start messing with stuff, sniff for juniper (Sense Trouble)! Müller comes riding back on a byakhee and the Big Fight ensues. Blowing up the sacred stone might dismiss the byakhee, or at least weaken its connection to Hastur.
Not a particularly challenging scenario, I admit. But it makes a nice, straightforward monster-of-the-week, and still has enough weird juju to keep the players happy and creeped out, especially if you run it with any or many of the variations on the monster from the rest of that Hideous Creatures installment. As a bonus, see if you can get some extra inspiration from the Manly Wade Wellman story “O Ugly Bird!” which is not at all about a byakhee, unless it is.
Archaeology: The Parthenon was oriented to the rising of the Pleiades – perhaps this temple shared the same alignment. In which case, the high altar should be over here. (Architecture, Astronomy)
Art History: The black-winged demon tormenting St. Anthony in Matthias Grünewald’s Isenheim Altarpiece (1515) is supposed to be the result of an ergot hallucination – so why does it perfectly match the eyewitness’ description of the “devil bird” that took Kerenyi right out from under our noses?
Assess Honesty: He claims that the winged monsters and the flying through space was all a dream brought on by drinking “too much mead” – but he doesn’t believe his own denials! Is he crazy, or is he driving himself crazy thinking he’s crazy?
Biology: The grass here was frozen and then broken from the top down, as though something unutterably cold landed here. The spores growing here are new – I’ve never seen anything like them before, although they slightly resemble nitrogen-fixing fungi.
Chemistry: The parchment and ink are absolutely authentic for a print struck in Colmar during Martin Schongauer’s life (1440-1491). But why would he run off a print study of just one of the demons in his Torment of St. Anthony? (Art History, Document Analysis)
Cryptography: The symbol cut into the crystal is Agrippa’s emblem for the Pleiades. (Occult, q.v.)
Evidence Collection: The prints generally resemble those of carrion birds, but are not deep enough to indicate anything heavy enough to batter a human ever stood in them. (Outdoorsman)
Forensics: The body is slashed and torn almost to rags, and blood spatter evidence indicates it was carried around the area during the struggle. Although the throat is ripped out, there is surprisingly little blood either on or in the corpse.
Geology: This whistle isn’t made of any kind of stone I’m familiar with. It seems like iridium-bearing ore, rather than the natural alloy one expects to find. It could be igneous rock or clay, subjected to intense heat – possibly meteoric in origin, as I’ve never seen anything like it on earth.
History: This whole Alsace-Lorraine region was a hotbed of witchcraft outbreaks from 1410 to 1690; testimonies (not all extorted by torture) record witches and wizards flying to the Bavarian Alps (or the court of the Devil) at unearthly speed on their demonic steeds after drinking a golden potion.
Languages: The tablet we found in her sink is inscribed in ancient Babylonian, beginning with MUL.MUL, the “Star of Stars” or the Pleiades. The basalt stone is incredibly weathered, but the cuneiform looks like it was carved yesterday. (Geology for stone)
Library Use: This is the 1511 Strasbourg edition of Euclid. It incorporates a number of “improvements” by the translator Bartolomeo Zamberti taken from Theon of Alexandria’s Catoptrica – the study of mirrors – and “Alhazen’s” De crepusculis – a treatise on shadows at twilight. Why go to the trouble to get this specific edition? Does it have anything to do with the mirrors set up to reflect the western horizon right on the Pleiadean alignment? (Astronomy)
Medicine: He’s suffering from shock and severe hypothermia – and those red spots all over his skin are purpura from exploded capillaries. The dark tan indicates high ultraviolet exposure, too.
Occult: According to Agrippa’s De Occulta Philosophia (1510-1530), a properly prepared talisman “with the Moon conjunct the Pleiades rising or at midheaven, preserves the eyesight, summons demons and the spirits of the dead, calls the winds, and reveals secrets and things that are lost.”
Oral History: Talking to peasants and townsfolk all through the area, you notice that some families are – not shunned, precisely, but less connected to the rest of the region. More insular, apt to marry among themselves. The Weylands and the Müllers seem to be the leading families in that group.
Pharmacy: I can’t tell what this so-called mead is supposed to be, but it’s not just fermented honey. Or if it is, the bees took pollen from a literally impossible collection of plants, fungi, and epiphytes, and then added some ethylene glycol and neurotoxic heavy metals to finish the job. This will either put you into a mild coma or give you the worst hyperaesthesia you’ve ever had. (Chemistry)
Sense Trouble: A waft of icy air seems to rush past you, and an astringent smell like rotting juniper stings your nostrils.
Theology: Shrewsbury’s work references the “earth-diver” myth of creation common amongst Siberian and Amerind peoples, in which a sky deity sends a (sometimes infernal or demonic) bird to the bottom of the ocean to raise up the land at the beginning of time. He thus postulates a primordial antagonism between Water-Chaos and Sky-Art, and implies these “demonic birds” also “dive” into our subconscious to raise up artistic and religious impulse.