Investigation Design Guide

This guide covers advanced techniques for designing compelling horror investigations. Building on the Three Clue Rule, these techniques help create mysteries that are challenging but solvable, atmospheric but playable.

📖 Prerequisites: Familiarize yourself with the Investigation Mechanics Guide before reading this advanced material.

🏗️ Mystery Structure

The Node-Based Approach

Design investigations as networks of "nodes" (scenes/locations) connected by clues. This creates non-linear investigations where players can approach from multiple angles.

Node Types

Core Nodes: Essential locations investigators must visit
Branching Nodes: Optional locations that provide alternative paths
Floating Nodes: Can be inserted anywhere when needed
Dead End Nodes: Red herrings that still provide atmosphere

Information Flows

Linear vs. Non-Linear

Linear: A→B→C→Resolution

Easier to prepare
Can feel railroaded
Good for new Keepers
Works for one-shots

Web Structure

Non-Linear: Multiple paths to resolution

More player agency
Requires more prep
Prevents single failure points
Better for campaigns

🔍 Advanced Clue Design

Clue Delivery Methods

Method	When to Use	Example
Passive Discovery	Core clues, automatic when in location	"You notice bloodstains on the floor"
Active Search	Secondary clues requiring investigation	"Searching the desk reveals hidden letters"
Skill-Gated	Expert knowledge, not critical path	"Medical exam reveals unusual poison"
NPC Testimony	Floating clues, social approach	"The janitor mentions strange sounds"
Document Research	Background information, context	"Old newspapers detail similar incidents"
Environmental	Atmosphere and mood setting	"The air smells of decay and ozone"

Layered Clues

Design clues with multiple layers of information based on investigator expertise:

Example: A Strange Book

Base Layer (Anyone): Old leather-bound book with strange symbols
Language Layer (Read Latin): It's a grimoire about summoning
Occult Layer (Occult skill): Specific ritual for calling Deep Ones
Mythos Layer (Cthulhu Mythos): Recognizes ritual from Necronomicon, knows consequences

⏱️ Pacing & Tension

The Investigation Curve

Act I: Discovery

Opening mystery, initial clues

Present the mystery
Establish atmosphere
Introduce key NPCs
Provide obvious clues

Act II: Investigation

Following leads, building tension

Multiple investigation paths
Complications arise
First supernatural events
Clues point to truth

Act III: Confrontation

Truth revealed, final choice

Full horror revealed
Investigators must act
Ticking clock pressure
Resolution (often pyrrhic)

Tension Techniques

Building Dread

Escalate supernatural manifestations gradually
Use atmosphere before revealing monsters
Create sense of being watched
Impose time pressure when needed
Harm NPCs before investigators

Release Valves

Provide moments of calm between scares
Allow dark humor to surface naturally
Give small victories along the way
Balance horror with mystery solving
Don't overdo sanity loss

🎭 Red Herrings & False Leads

⚠️ Important: Red herrings should arise naturally from player assumptions, not from deliberate GM misdirection. The Three Clue Rule means you shouldn't need to plant false clues.

Natural Red Herrings

Coincidence: Unrelated events that seem connected
Player Theory: Investigators jump to wrong conclusion
Incomplete Information: True clues that seem to point wrong way
Genuine Suspects: NPCs with secrets unrelated to main mystery

Handling Player Theories

When players develop elaborate theories that are wrong:

Don't confirm or deny too quickly
Provide new clues that contradict theory
Let them discover truth naturally
Sometimes their theory is better - consider using it!
Never punish creative thinking

✅ Testing Your Mystery

Pre-Game Checklist

☐ Every conclusion has 3+ clues supporting it
☐ Each clue can be found through different methods
☐ No single skill/character type is essential
☐ Floating clues prepared for when players get stuck
☐ NPCs have motivations beyond "provide clue"
☐ Multiple paths to resolution exist
☐ Sanity loss escalates appropriately
☐ Investigation can be completed in reasonable time
☐ Ending offers player choice, even if limited

Common Pitfalls to Avoid

❌ Don't Do This

Single critical clue
Clue requires specific action
Mystery depends on NPC survival
Solution requires specific skill
Deliberate misdirection
Unsolvable without lucky guess

✅ Do This Instead

Multiple paths to every truth
Reward any reasonable approach
Information survives NPC death
Alternative skills work too
Let players create theories
Deduction over guessing