Helpful Notes

Basic Rules

  • Success at a skill is a roll equal to or lower than the percentage.
  • Damage Bonus applies to hand held weapons.
  • Damage Bonus applies at 50% to thrown weapons.
  • Lost HP return at 1d3 HP per week.
  • When HP = 0 or less, the character dies at the end of the next round.
  • First Aid or Medical can immediately heal 1d3 HP.
  • First Aid or Medical success immediately wakens one Knocked Out .
  • First Aid can be applied once per injury.
  • Medical success increases HP return to 2d3 HP per week.
  • Grapple success holds opponent. Next round allows a grapple action.
  • To escape a grapple requires a STR match on the Resistance table.
  • Successful use of a Skill might gain a check mark – ask.
  • If a single wounds deals damage 50+% of current HP, roll CONx5 check for falling unconscious.
  • An investigator with HP = 2 or less, immediately falls unconscious.
  • If Stunned, can parry or Dodge only – lasts 1d6 rounds.
  • If Dodging you can also Parry, but cannot attack.
  • Derived Stats:
    • INT x 5 = Idea
    • POW x 5 = Luck
    • EDU x 5 = Know
    • HP = (SIZ+CON) / 2
    • MP = POW
    • Sanity = POW x 5.
    • DB = (STR+SIZ) on Chart (pg35 or 36)


  • Sanity equals POW x 5. Loss of POW = Loss of SAN.
  • 99-Cthulhu Mythos means, subtract Cthulhu Mythos points from 99 (i.e., start= 99-0) to calculate the Cthulhu Mythos percentile.
  • Cthulhu Mythos percentile is also Maximum Sanity points. Black out Sanity points as the percentile rises.
  • 5+ SAN loss to a single event requires Idea roll; success = Temp Insanity.
  • 20% SAN loss in one hour causes Indefinite Insanity for 1d6 months.
  • Current Sanity can be increased by:
    • Keeper Award: at the end of an adventure
    • Increasing POW: because SAN = POW x 5
    • Increasing a Skill to 90%: add 2d6 to current Sanity (discipline and self-esteem)
    • Defeating Unnatural Entity (thwart its goal): Keeper’s discretion; up to the entity’s Sanity loss

Helpful Notes

Barnum Institute of Science and Horror jimmorte