Advice for Running 'Edge of Darkness' for Call of Cthulhu 7e

'Edge of Darkness' is a chilling escalation from the standard entry to Call of Cthulhu in "The Haunting". A spiritual successor in tone, this beginner-friendly scenario trades the eerie quiet of a haunted house for a full-blown ritual to banish a Mythos entity. At its core is a simple question: Can the investigators atone for someone else's sins...or will they be devoured by the consequences?

This scenario is perfect for players who want more Mythos, more magic, and more moral ambiguity - without needing deep system mastery.

Scenario Overview:

• Title: Edge of Darkness
• Setting: Rural Massachusetts, 1920s
• Runtime: 1–2 sessions
• Themes: Occult rituals, cosmic atonement, undead horror
• Best For: Players seeking a spooky twist on “heroic” action, players coming from Pathfinder or D&D especially as it treats them to a different kind of encounter.

Review: A Sinister Séance in the Farmhouse

The story begins with a deathbed request. Rupert Merriweather, a man haunted by his past, begs the investigators to undo a ritual his occult group failed to complete decades ago. The setting—a secluded, warded farmhouse—is the stage for a tension-filled confrontation with the Lurker in the Attic and its disturbing thralls.

What Works:

• A True Mythos Ritual – This scenario is a template for climactic Call of Cthulhu rituals. Keepers need a plan! It is even more fun if the Keeper really puts work into the ritual, maybe including additional intricacies to build this portion of the Scenario.
• Creeping Build-Up – From eerie journal entries to strange attic sounds, dread slowly boils over. To do the scenario justice, this should be played up similarly to running "The Haunting".
• Dynamic Finale – The Lurker doesn’t just wait to be banished—it fights back, distracts, manipulates, and assaults.
• Perfect for D&D or Pathfinder Expats – The structure balances tension and agency without being too sandbox. It is front-loaded with lore, but in my experience even those looking for a little more action had a blast in the latter half and that drew them in for further scenarios.

What to Watch For:

• The Ritual Can Feel Too Easy – Many first-time Keepers think: “Wait, is this it? They just… chant and win?” Thankfully, this is easily fixed. I highly recommend building out the ritual into something with more depth.
• Front-Heavy Lore Delivery – Investigators get dumped with journals, documents, and backstory. New groups may feel overwhelmed if not paced correctly.
• Low Interactivity Without Modification – If the Lurker doesn’t actively resist, the finale falls flat.

Keeper Tips & Tricks:

1. Treat the Lurker as an Active Villain, Not a Passive Foe: The scenario notes that the Lurker From Beyond should interrupt the ritual. Here are some ways to weaponize the setting, so the Lurker is not simply waiting for them:

• Throw corpses down from the attic that animate once inside the warded room
• Use hallucinations or illusions to tempt players—e.g., “a vision of a dead mother calling to her child,” try not to give away that these are hallucinations immediately, have some of these seem in-character before the Investigators know what is happening.
• Have it manipulate devices: Use a stereo to blast music or the TV to show the original summoning to attempt to break the party’s concentration

2. Add Optional Rolls to the Ritual: Add some additional rolls to the ritual in order to spice things up, change what is needed to fit the ritual that you imagine is the most cinematic.

• DEX to time the powder
• Art/Craft or Occult to draw the pentagram
• POW/CON to maintain the chant
• Sanity checks when the Lurker tempts or lashes out

These create tension without derailing the mechanics—and make failure a real possibility.

3. Use Zombies Tactically: Don’t just send them shambling through the front door. Instead, have them peel away warding runes, bash through windows, or even bait players into breaking the circle.

4. Play with Time and Distraction: One popular tactic: have each investigator contribute 2 magic points every in-game 30 minutes, only if they aren't distracted or interrupted. Miss a CON roll? You lose your contribution. Fail a SAN check? The chanting breaks for everyone.

5. Prepare for Drama, Not Combat: Edge of Darkness isn’t about 'combat'—it’s about holding the line while your world falls apart and in the face of challenging odds. The investigators shouldn't feel like heroes, they should feel like they are barely holding it together.

Handout Design: Bringing the Darkness to Life

This scenario leans heavily on written material and the past sins of NPCs. That makes handouts essential to atmosphere and storytelling.

1. Rupert Merriweather’s Journal: The crux of the backstory. Make this a stitched leather-bound booklet with uneven, aged pages or a small hand-written journal from the Dollar store. Additional Suggestions can include water damage and ink smears, Handwritten entries, maybe with a bloodstain on the last page. If you don't have time to handwrite, look for a convincing handwriting font and print in around size 16 font. A separate envelope marked “Read Only When It’s Too Late” might continue a Hail Mary way to beat the Lurker, perhaps requiring a frightful decision such as a sacrifice of one of the Investigators.
2. The Last Will and Testament: Create a fake will document naming the investigators. Add: An official seal from “Emerson, Kline & Merriweather – Law Offices”, Scrawled postscript: “The box must go with them. They must know.”
3. Farmhouse Floorplan: A crude pencil sketch of the farmhouse. Direct the players knew to the attic with a thick ‘X’ over it and the words ‘DO NOT OPEN’ written in red pencil.”
4. The Ritual Materials List: Index card or crumpled page with key ritual items: Brown powder, Sealing salt, Latin incantation, Goat blood (crossed out, replaced with “sheep acceptable”), Bonus points for including the Latin chant as a separate handout for players to read aloud. Easily made with Google Translate. If doing so on a separate page, write it with a thick black charcoal pencil to make it look ancient.
5. Merriweather’s Box: Instead of just saying “you find a box,” if you want to go all out, present an actual wooden or cardboard container with: A powder (this can literally be anything in a bottle), Latin script, A newspaper clipping about a missing hobo. A photo of the Dark Brotherhood from decades prior (find a black and white photo or if you have access, you may be able to generate a half decent one using an image generator of your choice. Include “odd burn marks” on the outside with a lighter and a cracked mirror fragment inside—useless, but deeply unsettling.

Final Thoughts:

Edge of Darkness offers players something rare: the chance to right a cosmic wrong. It’s bleak, it’s atmospheric, and it’s incredibly rewarding when played well. And while it’s easy to run as-written, the scenario comes alive when the Keeper turns up the pressure.