Investigation Scenario Generator
Use these d100 tables to generate the core elements of a horror investigation. Roll on each table to create a unique mystery scenario, then flesh out the details based on your campaign setting and themes.
🔍 The Incident (d100)
What draws the investigators into the case?
| d100 | Initial Incident |
|---|---|
| 01-10 | Series of missing persons, all connected |
| 11-20 | Brutal murder with impossible circumstances |
| 21-30 | Friend or relative calls for help, then vanishes |
| 31-40 | Strange occurrence at specific location |
| 41-50 | Investigator receives cryptic warning or threat |
| 51-60 | Discovery of ancient artifact or document |
| 61-70 | Seemingly unrelated deaths follow same pattern |
| 71-80 | Witness to supernatural event seeks help |
| 81-90 | Hired to investigate by mysterious benefactor |
| 91-00 | Stumble upon conspiracy by accident |
👥 The Victims (d100)
Who is affected or targeted?
| d100 | Victims/Targets |
|---|---|
| 01-10 | Local teenagers or young adults |
| 11-20 | Members of specific profession or organization |
| 21-30 | Residents of particular neighborhood |
| 31-40 | People with specific bloodline or ancestry |
| 41-50 | Those who witnessed something they shouldn't have |
| 51-60 | Random victims with no apparent connection |
| 61-70 | Family members across generations |
| 71-80 | People involved in past event or tragedy |
| 81-90 | Those who possess something valuable/dangerous |
| 91-00 | Investigators themselves are the true targets |
📍 The Location (d100)
Where does the mystery center?
| d100 | Central Location |
|---|---|
| 01-05 | Abandoned asylum or hospital |
| 06-10 | Old mansion or estate |
| 11-15 | University or research facility |
| 16-20 | Small isolated town |
| 21-25 | Historic hotel or inn |
| 26-30 | Ancient burial ground or cemetery |
| 31-35 | Derelict industrial site |
| 36-40 | Museum or gallery |
| 41-45 | Theater or performance hall |
| 46-50 | Church or monastery |
| 51-55 | Library or archive |
| 56-60 | Underground tunnels or catacombs |
| 61-65 | Lighthouse or coastal installation |
| 66-70 | Private club or society |
| 71-75 | Forest or wilderness area |
| 76-80 | Boarding school or orphanage |
| 81-85 | Sanitarium or rest home |
| 86-90 | Corporate headquarters |
| 91-95 | Archaeological dig site |
| 96-00 | The investigators' own city/neighborhood |
😈 The Culprit (d100)
Who or what is responsible?
| d100 | Culprit/Antagonist |
|---|---|
| 01-05 | Organized cult serving dark entity |
| 06-10 | Single mad sorcerer or cultist |
| 11-15 | Vengeful spirit or ghost |
| 16-20 | Mythos creature (Deep One, Ghoul, etc.) |
| 21-25 | Possessed individual(s) |
| 26-30 | Secret society with hidden agenda |
| 31-35 | Experiment gone wrong |
| 36-40 | Cursed artifact or location |
| 41-45 | Ancient evil awakening |
| 46-50 | Dimensional intrusion |
| 51-55 | Serial killer with occult knowledge |
| 56-60 | Corporate conspiracy covering up truth |
| 61-65 | Government or military project |
| 66-70 | Descendant continuing ancestor's work |
| 71-75 | Rival investigator gone too far |
| 76-80 | Shapeshifter or doppelganger |
| 81-85 | Undead creature (vampire, zombie, etc.) |
| 86-90 | Alien intelligence |
| 91-95 | Someone investigators trust |
| 96-00 | No single culprit - cosmic indifference |
💀 The Motive (d100)
Why is this happening?
| d100 | Motive/Purpose |
|---|---|
| 01-10 | Summoning or awakening great power |
| 11-20 | Revenge for past wrong |
| 21-30 | Achieving immortality |
| 31-40 | Opening gateway to another realm |
| 41-50 | Gaining forbidden knowledge |
| 51-60 | Fulfilling ancient prophecy |
| 61-70 | Breaking or enacting curse |
| 71-80 | Survival - feeding or sustaining entity |
| 81-90 | Power and control over others |
| 91-00 | No comprehensible motive - alien logic |
🔄 The Twist (d20)
Optional: Add a complication or twist to the investigation:
| d20 | Twist |
|---|---|
| 1 | One investigator is unknowingly connected to the mystery |
| 2 | The authorities are complicit or corrupted |
| 3 | Victims were willing participants initially |
| 4 | Multiple groups working at cross-purposes |
| 5 | The location itself is alive or sentient |
| 6 | Time is not linear here |
| 7 | Culprit is trying to stop something worse |
| 8 | Investigation is part of larger plan |
| 9 | True danger hasn't revealed itself yet |
| 10 | Can't be stopped, only delayed or escaped |
| 11 | Everything that's happened already occurred before |
| 12 | Victim and culprit are same person |
| 13 | Investigation itself causes the danger |
| 14 | Evidence points to impossible conclusion |
| 15 | Everyone involved is already dead |
| 16 | Investigators are unwitting pawns |
| 17 | Truth would cause more harm than mystery |
| 18 | Solving it dooms investigators |
| 19 | No solution exists - only choices |
| 20 | Reality itself is the real problem |
📝 Example Investigation
Rolls: Incident (45), Victims (73), Location (11), Culprit (06), Motive (24), Twist (4)
The Whitmore University Disappearances
The Incident: An investigator receives cryptic warnings about "the awakening at Whitmore."
The Victims: Faculty and students who were involved in a controversial archaeological dig 10 years ago.
The Location: Whitmore University, particularly the anthropology department and museum basement.
The Culprit: A single mad professor who has discovered forbidden knowledge.
The Motive: Achieving immortality through an ancient ritual.
The Twist: Multiple groups are working at cross-purposes - the professor, a protective cult trying to stop him, and university administration covering everything up.
💡 Using This Generator
Building Your Mystery
- Roll on each table to get core elements
- Combine results into coherent narrative
- Add your own details and NPCs
- Create 3+ clues per major conclusion
- Plan for multiple investigation paths
Customization Tips
- Reroll results that don't fit your setting
- Combine multiple victims or culprits
- Add red herrings and false leads
- Scale difficulty to investigator experience
- Link to ongoing campaign threads