How to Play Eldritch Horror: Actions, Encounters & Mythos
Eldritch Horror is a cooperative global adventure game. Investigators travel around the world, gather assets and clues, resolve encounters and try to solve three Ancient One Mysteries before the global situation collapses.
Scope: Fantasy Flight Games base game only, without expansion mechanics.
Each round has three phases
- Action Phase: investigators move, rest, trade, acquire assets and use component actions.
- Encounter Phase: each investigator resolves one encounter at their location.
- Mythos Phase: draw and resolve a Mythos card, advancing global threats.
Investigators take two actions
During the Action Phase, each investigator normally performs up to two different actions. Travel moves across the map; Rest recovers Health/Sanity when legal; Trade exchanges possessions with another investigator; Acquire Assets uses Influence in a city to buy from the reserve.
Encounters depend on location
City, wilderness and sea spaces use location encounters. Gates, Clues and Expeditions can replace the normal encounter with special decks or tests that advance other objectives.
Tests use investigator skills and dice
When an encounter calls for a skill test, roll dice based on the relevant skill plus modifiers. Successes determine the result, with possessions, Conditions and investigator abilities modifying many tests.
Mythos cards escalate the board
Mythos effects can advance Doom, move the Omen, spawn Gates and Monsters, generate Clues or Rumors and trigger Reckoning effects. The icon strip determines the exact sequence.
Solve three Mysteries
Each Ancient One has a unique Mystery deck. Complete the current Mystery’s printed condition, then reveal the next. Solving three Mysteries normally wins before the Ancient One awakens; after awakening, the Ancient One’s Final Mystery rules apply.
Publisher reference: Fantasy Flight Games base rulebook and reference guide. Checked September 21, 2026.