Gameplay

Eldritch Horror is a cooperative game. All players are on the same team and win or lose the game together. The investigators' ultimate goal is to banish the Ancient One from this world by solving Mysteries. In addition, investigators need to deal with many threats and crises facing the world. These appear in the form of Gates (which spawn Monsters and can awaken the Ancient One) and Rumor Mythos cards (which harm investigators and can end the game prematurely).

## Playing the Game

The mechanism represents a set of events in a very abstract way. A single round in Eldritch Horror represents multiple days. For example, you can take a ship across the entire Pacific Ocean (a 2-3 week voyage by steam ship in the 1920s) in a single round. A single Gate token represents numerous portals and other anomalies across a city like Arkham. And each Monster token doesn't necessarily represent exactly one monster of exactly that type. A combat encounter can also include being hunted (or hunting it) in a city. Nor does not gaining a bonus represent not using that resource; if you have an Axe and a Hired Muscle, the +2 bonus from the axe just represents the greatest resource you have in the fight. The reroll from the hired muscle which stacks with the bonus from the axe is him helping you, even if he's not going to be as harmful as you with an axe. Or you're  Charlie Kane and you just hand the hired muscle your axe and let him handle the monsters; the axe is still more harmful than the hired muscle's fists.

Eldritch Horror is played over a series of game rounds. Each round consists of three phases that are resolved in the following order, beginning with the Lead Investigator:

1. Action Phase: Investigators perform actions to move about the game board and prepare for the tasks ahead.
2. Encounter Phase: Investigators fight Monsters or resolve encounter cards on their current space.
3. Mythos Phase: The Lead Investigator resolves one Mythos card. These cards often advance the  Doom token, spawn Gates, or raise other challenges that investigators will need to overcome.

Every investigator completes the first phase before moving on to the next one. At the end of each Mythos Phase, the Lead Investigator may pass the Lead Investigator token to any player of his choice. Investigators then start a new game round beginning with the Action Phase. Players continue resolving game rounds until they have won or lost the game.

### Setup

*Main article: Setup*
Before playing each game, the players may perform many steps in a particular order consisting of placing the different components and organizing the decks, choosing investigators and Ancient Ones, or using optional cards such as Preludes, Adventures or Personal Stories.

### Action Phase

*Main article: Action Phase*

During the Action Phase, each investigator may perform up to two actions. The Lead Investigator performs his two actions first, then proceeding clockwise around the play area, each other investigator performs his two actions. Investigators may perform the following actions:

* Rest
* Travel
* Trade
* Prepare for Travel
* Acquire Assets
* Focus
* Gather Resources
* Component Action

### Encounter Phase

*Main article: Encounters*

After the Action Phase is completed, the Encounter Phase starts. The Lead Investigator resolves an Encounter completely, undertaking every action. Play then proceeds clockwise, just as it would for the Action Phase.

Any investigator in a space containing Monsters must resolve a Combat Encounter with all monsters on his space, unless the player has an ability that prevents these encounters. The player resolves the encounter with every monster, one at a time, in whichever order the player chooses. However, starting from the expansion Forsaken Lore, if there is an Epic Monster on the space, he must encounter all non-Epic Monsters before encountering the Epic Monsters. If after the Combat Encounters there are 0 Monster on his space, he may resolve 1 other encounter, either location or token of his choice, otherwise it ends.

All Combat Encounter are queued before any encounters are resolved. This queue of Combat Encounters is part of the reason the Mists of Releh Spell could not be used to avoid some of the Monsters on an investigator's space. The Spell's effect is resolved before the Combat Encounters are added to the queue. Once the encounters are queued, very few effects can stop them from happening, one of which being the investigator is defeated.

Depending on the space the investigator is on, he could resolve one of the following:

* General Encounter
* Location Encounter
* Research Encounter
* Expedition Encounter
* Mystic Ruins Encounter
* Other World Encounter
* Dream-Quest Encounter
* Devastation Encounter
* A specific Mystery, Adventure, or Rumor may have the investigator perform an action "instead of an Encounter."
* The Detained or Lost in Time and Space Conditions will trigger during this phase.

If the investigator has an Asset that resolves after an encounter, like Mineralogy Research or Courier Run, complete that action after the Encounter is undertaken, but before the next player goes. If more than one type of encounter is applicable on the space, the investigator may choose from the available choices.

### Mythos Phase

*Main article: Mythos*
The lead investigator draws the top card of the Mythos deck and performs the actions indicated in the order they appear. These actions can be:

* Advance Omen
* Resolve Reckoning Effects
* Spawn Gates
* Monster Surge
* Spawn  Clues
* Place  Rumor Token
* Place  Eldritch tokens

Resolve all effects on the top of the card before reading the flavor text and the Event or Rumor on the bottom of the card.

## Winning the Game

Investigators immediately win the game if they solve enough Ancient One’s Mysteries as list on its sheet, usually three. If the Ancient One awakens,
investigators will also need to solve the Final Mystery in order to win the game.

In the rare circumstance that both winning and losing effect happen at the same time, investigators win the game.

Investigators lose the game if any of the following occur:

* If the Doom token reaches the "0" space of the Doom track, the Ancient One awakens. The back of the Ancient One sheet lists how investigators can lose the game.
* All investigators have been eliminated from the game.
* A card effect causes investigators to lose the game. This most frequently appears on some Rumor Mythos cards.
* The investigators are required to draw a Mythos card but cannot because the Mythos deck is empty.

## Scoring

If investigators win the game, they can determine how well they did and record this score on a sheet of paper along with the Ancient One and any optional rules used. The lower the score, the better!
To calculate a score, start with 0, then:

* Add 1 for each Gate on the game board.
* Add 1 for every 3 Monsters on the game board (rounded up).
* Add 1 for each Cursed or Dark Pact Condition investigators have.
* Add 3 for each Rumor Mythos card in play.
* Subtract 1 for every  3 Clues tokens investigators have (rounded up).
* Subtract 1 for each Blessed Condition investigators have.
* Subtract the current level of Doom.

## References

1. ↑ Official answer from Nikki Valens for mechanism on  *BoardGameGeek*.
2. ↑ Official answer from Nikki Valens for combat queue on  *BoardGameGeek*.