Cthulhu Abides is a Pick-Up & Play (PUAP) RPG inspired by the horror fiction of H.P. Lovecraft.
Character creation can be carried out with a series of rolls or choices on tables that generate details of Investigators' physical, mental and social capabilities as well as their philosophy and goal in combating the Mythos.
The game employs a Dynamic Madness system in which getting moire insane unlocks new powers and insights as well as being socially and behaviourally debilitating. During a Story, characters' sanity will rise and fall in response to stressors and sedators, some of which are unique to the character.
The core mechanic is a 'poker dice' resolution system, involving rolling d6s and totalling the matching dice or taking the highest single score. Bonuses are added to this reflecting skill and situational variables. There are no 'hit points' or wound levels. Investigators are frail mortals who are killed or stunned by wounds but can build up elaborate 'resists' by choosing maiming injuries, psychological trauma, falls and disarms.
Investigations are conducted by gathering different sorts of Clue Points, picked up by good roleplaying, deductive thinking or lucky dice rolls. Clue Points are traded for access to deeper levels of the Story or Bonuses to be used in the final Denouement or Ordeal.
A freeform Magic System lets Investigators create unique Spells at great psychological cost. Investigators may infiltrate Cults and Elder Ruins to gain advantages against their enemies and cross the Angles into other realities.
Monsters and Gods of the Mythos are reinterpreted and described along with rules for the ecstatic Transfigurations brought on by these encounters that grant powerful insights but rob Investigators of their humanity.
The Dreamlands of H P Lovecraft's fantastic fiction are reinterpreted along Freudian lines and lists of research Archives, esoteric Cults and ruins in 1920s Britain are presented.