This module was my first experience running (and writing for) Trail of Cthulhu and it was a blast to play. The GUMSHOE system really does a lot of heavy-lifting and happily shunted the mechanics my way — at times it felt like there really wasn’t much of a system at all.

I’m often loath to begin with pre-con modules. This is how we started for a Purist game.

In my clue descriptions, I rarely keyed in a specific ability. Instead, I’ve listed CoreSurface & Obscure clues – the last being either available for a perfectly suited investigator, a point-spend, or good RP decisions.

^ { ; , ; } ^

 The Hook

An old friend of one of the PCs, Nigel Oraunt, has been working as a lawyer overseas for years. He contacts his old friend because he has something esoteric he wants to discuss before an important meeting with an underground railway company. Overnight, he vanishes from his locked hotel room.

The Horrible Truth

The secretary of the underground company, Henry Eastleigh, has been pushing forward plans for years to alter the route of the trains — the current network is consciously in the shape of a locking glyph to protect London from extradimensional beings. Eastleigh hopes to release this lock and use ancient dhole tunnels to bring these enormous worms back to Earth.

Eastleigh is the head of a local cult operating out of an esoteric book store. He has caused Oraunt to vanish through his summoning and binding of a formless spawn of Tsathoggua and has stolen the artefact Oraunt was going to show the underground company.

The Spine

While the following events are numbered, there is no compulsion to complete them in order. That said, Number One should come first & Number Nine is the narrative climax.

  1. investigate Oraunt’s empty room; note spawnslime & missing crate
  2. interrogate porters & concierge; learn crate’s been stolen & sold to bookshop
  3. investigate sewers; find twisted corpse of Oraunt
  4. investigate the fixer who organised the theft & sale of the crate
  5. follow up Oraunt’s meeting with tube staff; note strange art & secretary’s odd manner
  6. meet tube boss; he laughs off arcane theories, Eastleigh offers to meet
  7. visit worksite; see evidence of formless spawn & infer the tunnel’s ancient construction
  8. cult rooms beneath bookshop; cult have been trying to destroy contents of crate, evidence of summoning ritual
  9. confrontation with Eastleigh

^ { ; , ; } ^

Oraunt’s empty room

The party member with the highest occult / book pools gets a message from the hotel concierge, Simmons, asking them to come as soon as possible. Simmons is efficient and discreet and his black hair is always perfectly slicked back. Simmons reveals that Oraunt went missing from his room last night & that they were to be contacted “if anything strange happens”.

Core: Simmons has a letter, detailing Oraunt’s plans to meet with the tube staff to show them the artefact he carries.

Surface: Cops have been to the scene but feel the whole vanish is an elaborate scam for insurance fraud.

Oraunt’s room has been left in the state that housekeeping found it in: his stuff is partially unpacked and the bed linen is crumpled up.

S: No sign of forced entry, window painted shut, room key on dresser.

Obscure: A strange condensation on the inside of the glass & on the window pane – smeared fingerprints in these.

S: Sluglike trails around the toilet and on some of the nearby surfaces: something has been gone into the sewers

Core: The desk in the room shows signs of having been rapidly rooted through. Something large has been taken. The porters should remember Oraunt’s luggage.

^ { ; , ; } ^

Porters & concierge

Simmons gathers the porters who were working last night.

S: The porter who handled Oraunt’s stuff is hiding something. His name is Aaron Task and is early twenties, though looks like he’s still suffering through puberty.

Core: That porter stole the case: it was stolen to order by a fixer he’s not worked with before for an occult bookshop called Tannens.

O: The porter heard weird sounds from the toilet during the night in Oraunt’s room: made him feel uncomfortable.

^ { ; , ; } ^


Beneath the hotel, there are more signs of the weird slug-trail slick, though not as dry as that in Oraunt’s room.

Core: A badly twisted skeleton is stuck to the wall: its bones have been warped out of natural shape. Grisly scene requires 2 point Stability check.

S: The skeleton is stuck to the wall with the same slick as is on the surfaces.

O: The slick is highly susceptible to flame: essentially melts away at its presence.

S: The bones have not been here long: this is a very recent death. However, the bones have been picked clean as if by acid.

S: Anyone who knew Oraunt in life will recognise the piece of shrapnel in his shoulder from his old WWI wound. Corpse of friend requires 2 point Stability check.

^ { ; , ; } ^


To spike a little jeopardy into the early section of this investigation, and to ensure the players know how to handle combat for the climactic final fight, there should be a short combat either as players leave the sewers or head to meet the fixer. Either a swarm of rats or a mugger, either way with: Athletics 4, Health 4, Scuffling 4; -1 knuckleduster / bite.

^ { ; , ; } ^

The fixer

Harry Rafters is an old east-end criminal with a lot of connections. He talks with a typical east London scrawl and has an angry white scar down the side of his head, just above the ear. He frequents a pub in Whitechapel.

Core: He’s stolen for Tannen’s (the bookshop) before, to the order of Henry Eastleigh. Essentially he sets up people in the right place at times he’s been told of.

S: This time, he also sourced sewer schematics for Eastleigh.

O: He is becoming under the influence of the cult. He will inform Eastleigh that questions have been asked unless he is sufficiently intimidated &c. into not doing so.

^ { ; , ; } ^

Meeting with tube staff

James Mackay was scheduled to meet with Oraunt yesterday, as the receptionist, Ms Elaine Trappist, will be happy to reveal. Ms Trappist is a career administrator: she’s very good at her job, wears immaculate grey suits perfectly matching the colour of her hair. Her tortoiseshell glasses are the only splash of colour.

Mackay isn’t in this afternoon: he’s gone to visit some of the worksites. Ms Trappist leaves to fetch Henry Eastleigh. Eastleigh is a nondescript man with puffy face and thin neck. His tie knot is ever-so-slightly too small.

S: While waiting, the players may notice some weird art in the lobby. This is something Eastleigh has had installed & Ms Trappist doesn’t like it. If the players spent any time studying the image, they recognise that it’s impossibly old: older even than cave paintings. The image depicts gargantuan worms — dholes. This realisation triggers a 3 point Stability check.

Core: Eastleigh arrives and will happily discuss any fears with the party. He is happy to arrange another meeting with Mackay in the near future. If the party reveal anything about Oraunt’s disappearance or the missing crate, he keep his involvement hidden. However, if they visit the worksite or the bookshop, Eastleigh will have them trailed by cultists.

S: Eastleigh is holding a package with the address of Tannen’s bookshop on it. He is very careful to clutch it close.

S: Ms Trappist can helpfully reveal the location of the worksite: just south of Oxford Street.

^ { ; , ; } ^

Meet tube boss

James Mackay is the head of the underground company. He is very tall and very broad, though generally thickset rather than obese. He has an unruly mess of stiff blond hair and is always cleanly shaven. Eastleigh will be present in the meeting. Mackay is very dismissive of Oraunt’s initial fears and doesn’t understand why a foreign lawyer would need to get involved in British transport decisions. He openly laughs at any suggestion of supernatural threat.

Core: In the lobby, Eastleigh hints to the team that he’s aware of the kind of things they’re researching. He offers to meet them at Tannen’s. He’s good at lying: a spend of Assess Honesty or a Sense Trouble check (target: 5) will be required to be certain it’s an ambush.

^ { ; , ; } ^


The site is generally closed off to the public, but a persistent party can get in with a simple Athletics check (target: 4). Failure means noise: it draws the attention of anything on-site and nearby policemen. If they get inside quietly, a successful Sense Trouble check (target: 5) will spot the formless spawn retreating — any characters that observe the creature suffer a 4 point Stablity check (target:5).

Core: There is a partially digested guard near the entrance to the greater tunnels. Half of his body has been stripped to the bone. This particularly grisly body incurs a 3 point Stability checkif a player has seen the formless spawn, failing the check causes a 4 point loss instead. The guard is slick with slugslime.

O: Any geological or architectural understanding shows these tunnels have been naturally bored & are very, very old.

If Eastleigh is paranoid, there will be a number of cultists here equal to one more than the number of players. Each cultist has: Athletics 7, Flee 5, Health 8, Scuffling 7; they are armed with -1 tools.

^ { ; , ; } ^


Tannen’s is a fairly ordinary looking – if tacky – esoteric bookshop in the heart of Bloomsbury. It’s owner, Helen Tannen, is a cultist but is terrified of Eastleigh & clearly holding back information. Tannen is somewhat jowly and has a near-permanent smile in her eyes; her hair is a mass of thick brown curls & she always wears oversized cardigans with the sleeves pulled low over her hands.

O: If she is broken, she will reveal information that points to the fact that Eastleigh has successfully summoned a creature. However, she is amnesiatic of most of the details. She refuses to go downstairs.

While upstairs is open to the public, downstairs is the cultist’s base. It shouldn’t be too difficult to get past Tannen. How the party do so is up to the players: failed checks will result in them leaving evidence (& alerting Eastleigh).

Core: Oraunt’s case is downstairs on a workbench. There are a number of destructive materials nearby – they have been attempting to destroy the artefact but have failed to do so.

S: Close study of the artefact — a bas relief depicting dholes and the locking glyph. This glyph forms the same shape as the current underground network. If the new tunnels at the worksite are instead used, it will break the glyph and enable the monstrous worms to be summoned. Spending any time looking at the artefact will incur a 3 point Stability check.

Core: There are scrawled notes in Eastleigh’s handwriting that details the worksite and explains how the work needs to be pushed along. Some of the men are working slowly because of the otherworldliness of the location.

O: In a larger ritual room downstairs, there are remnants of the same slugslime from before. Nearby there are a number of oxyacetylene torches.

^ { ; , ; } ^

Confrontation with Eastleigh

Before his planned ambush, Eastleigh will have killed Tannen – her throat is roughly slit and her corpse sits at the table, needing a 2 point Stability check.

Eastleigh plans to attack the team as soon as they are able to. He will try to draw the fight towards the formless spawn in the ritual room, though as the fight goes on the binding spell begins to wear off & it will start to attack the cultists.

Eastleigh has: Athletics 9, Health 9, Weapons 9, Scuffling 3; his Hit Threshold is 4; he wields a +0 oxyacetylene torch. If Eastleigh is killed, the formless spawn will vanish from this plane.

There are a number of cultists present equal to the number of players. Each cultist has: Athletics 7, Flee 5, Health 8, Scuffling 7; they are armed with -1 hardwood wands.

The formless spawn of Tsathoggua has: Athletics 12, Health 8, Scuffling 20; a Hit Threshold of 4; it can attack with a -1 tendril, a +0 limb and a +1 pseudopod; it is immune to all damage that is not caused by flame. Seeing the formless spawn requires a 4 point Stablity check (target:5), and the same again if watching it consume someone. If Eastleigh is killed, the formless spawn will vanish from this plane.

^ { ; , ; } ^


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