Arkham Horror (Third Edition): Under Dark Waves Rulebook

Table of Contents

Table of Contents

• Using this Expansion
• Expansion Icon
• Components
• Expansion Rules
  • Map Tiles
  • Neighborhood Tiles
  • Encounter Icons
  • Movement During Encounters
  • Travel Routes
    • Travel Route Cards
  • Mysteries
  • Complex Encounters
  • Expanded Neighborhood
  • Terror
    • Terror Tokens
    • Doom
    • Mythos Tokens
• Clarifications
  • Spawn a Clue
  • Monster Cards
  • Effects that Target Assets
  • Searching for Specific Traits
• Game Modes
  • Story Mode
  • Challenge Mode
  • Inevitable Mode
    • Inevitable Mode Rules
• Quick Reference
  • Encounter Icons
  • Mythos Token
  • Travel Route Types

Using this Expansion

When using Under Dark Waves, add the expansion's components to your collection as follows:

• Add the investigator and scenario sheets, investigator standees, map tiles, and all tokens to their respective supply pools.
• Shuffle encounters, headlines, allies, items, and spells into their respective decks.
• Sort archive, special, starting, condition, and monster cards into their respective decks.
• Separate anomaly, terror, and event decks for use as instructed in each scenario. Do not mix the event cards into the encounter decks.

Expansion Icon

Each card in this expansion is marked with the Under Dark Waves expansion icon to distinguish it from cards in the base game and other Arkham Horror products.

Components

• 2 Neighborhood Map Tiles
• 8 Travel Route Tiles
• 1 Mystery Tile
• 8 Investigator Sheets, with matching token
• 4 Scenario Sheets
• 4 Headline Cards
• 60 Archive Cards
• 12 Anomaly Cards
• 24 Terror Cards
• 104 Event Cards
• 72 Encounter Cards
• 21 Monster Cards
• 8 Condition Cards
• 8 Asset Cards
• 25 Starting Cards
• 14 Special Cards
• 4 "3 Damage" Tokens
• 3 Marker Tokens
• 6 Mythos Tokens
• 18 Terror Tokens (14 "1 terror", 4 "3 terror")

Expansion Rules

Map Tiles

Under Dark Waves introduces two hexagonal neighborhood tiles, an assortment of travel route tiles, and one mystery tile.

Neighborhood Tiles

The hex-shaped neighborhood tiles in Under Dark Waves represent locations in the coastal towns of Innsmouth and Kingsport. Neighborhoods in these towns are indicated by different name plates, to make them easily distinguishable from Arkham neighborhoods.

Name plates for Innsmouth Village and Kingsport Harbor neighborhoods.

When an effect refers to a town by name, the effect refers to neighborhoods with that name in the title as well as each street and each mystery tile connected to those neighborhoods. Neighborhoods that do not include a town name in their title are Arkham neighborhoods.

Example: An effect states, "Each investigator in Innsmouth suffers one horror." Each investigator in Innsmouth Village, in Innsmouth Shore, or in a street space or mystery adjacent to those neighborhoods is affected.

Encounter Icons

Some locations feature new encounter icons to indicate the payments or rewards an investigator is likely to find in encounters there, as follows:

Payments	Rewards
Suffer Damage	Move an Investigator
Suffer Horror	Spawn a Clue

Movement During Encounters

Some encounters may allow an investigator to move one or more spaces. You cannot move as part of such an effect while engaged with one or more monsters, unless that effect also specifies that you disengage any monsters. If you move into a space with one or more ready monsters that would engage you, those monsters engage you and your movement ends as normal.

Travel Routes

Travel routes are single-space tiles that allow investigators to move between the towns of the Miskatonic River Valley. There are three types of travel routes, each indicated by an icon:

• Country Roads
• Ferry Terminals
• Train Platforms

While moving voluntarily, whether as part of a move action or as part of another effect, an investigator in a travel route space may spend $1 to move from that space to another travel route space of the same type, in addition to the rest of their move.

Example: As her move action, Stella Clark moves from Hibb's Roadhouse to an adjacent ferry terminal (1). She pays $1 to move to another ferry terminal (2) and then uses her second space of movement to move to St. Erasmus's Home (3).

Treat travel routes as street spaces for all effects that reference such spaces, with the exception of encounters. Travel routes have their own encounter deck. During the encounter phase, if you are on a travel route and are not engaged with a monster, draw a card from the travel route encounter deck and resolve the effect that matches the type of travel route space you are on.

Travel Route Cards

Travel route encounters can have a variety of effects, but all travel route encounters include an opportunity to move to another travel route of the same type without cost. When an effect instructs you to move to another travel route space, move directly to that space. If there is no other space of the indicated type, do not move.

Mysteries

Mysteries are places of power and madness that offer encounters that are more rewarding, yet more dangerous, than those found in other locations. There are two mysteries included in Under Dark Waves: Devil Reef and the Strange High House. These are unique spaces that are added to the game board as indicated by some scenario setup maps.

A mystery is adjacent to any other space with which it shares a border. Investigators and monsters can move into mystery spaces as they would any other space.

Each mystery has a corresponding deck of encounter cards. During the encounter phase, if an investigator is on a mystery space and they are not engaged with a monster, they draw and resolve an encounter card from that mystery's deck.

Complex Encounters

Unlike other location and street encounters, mystery encounters provide divergent paths that depend on the choices that the investigator resolving that encounter makes. Each mystery encounter card contains three sections of effect text for the same location.

To resolve a mystery encounter, first resolve the top effect, which offers a choice regarding how to proceed; each option is presented in bold type. Then, resolve one of the other two effects, under the header that matches your choice. Do not read the secondary effects before making your choice.

Example: During an encounter at Devil Reef, Silas Marsh is caught in a storm, and the first encounter effect reads, "You may race into port or batten down the hatches to outlast the storm." He chooses the latter option, and resolves the bottom effect with the header, "Batten Down the Hatches."

Expanded Neighborhood

Each mystery tile is part of the neighborhood to which it is connected. If an effect places doom in a mystery space, that doom is counted with the rest of the connected neighborhood for the purpose of resolving any effects that count the total number of doom tokens in a neighborhood, including anomalies and terror.

Example: The Strange High House mystery is connected to the Central Kingsport neighborhood. The Strange High House mystery encounter card deck is in play.

Terror

Terror represents a neighborhood becoming overrun with madness and fear. The spread of terror across the board is indicated with terror tokens that are placed on the board and in the mythos cup, and with terror cards that are attached to neighborhood encounter decks.

These components are used by specific terror scenarios. There are multiple sets of terror cards, and each set is used by a different scenario as indicated on that scenario's sheet. The encounters represented on these cards are called terror encounters, which are described later.

In addition to the terror cards and tokens, each terror scenario adds archive card 61 ("Terror") to the codex and uses the following rules, which are summarized on that archive card.

Terror Tokens

The most common ways that terror tokens are added to the board are by the spread terror mythos token or when too much doom accumulates in a neighborhood.

Doom

When a neighborhood has a total of six doom, remove all the doom from one space in that neighborhood and place one doom on the scenario sheet. Then, spread terror in that neighborhood as described in the next column.

Mythos Tokens

Setup and codex effects in terror scenarios can also add the "spread terror" mythos token to the mythos cup. When you draw a spread terror token, spread terror in the unstable space's neighborhood as described in the next column.

Spread Terror

To spread terror, place one terror token in the indicated neighborhood. Then, attach the top card of the terror deck to that neighborhood by laying that card across the top of the neighborhood's encounter deck, perpendicular to the rest of the deck. A neighborhood may have any number of terror tokens or attached terror cards.

Example: There is a total of six doom in Kingsport Harbor, so the investigators remove three doom from St. Erasmus's Home (1), place one doom on the scenario sheet (2), and spread terror by placing one terror token in the neighborhood (3) and attaching one terror card to the neighborhood's encounter deck (4).

When you spawn a clue in a neighborhood with one or more attached terror cards, shuffle the event card into the top of the encounter deck as normal, not into the attached terror cards.

If an effect instructs you to spread terror and no cards remain in the terror deck, place one doom on the scenario sheet instead.

Terror Encounters

Before you resolve an encounter in any space of a neighborhood with one or more attached terror cards, first resolve an encounter using one of those terror cards, chosen at random. After resolving the terror encounter, you may resolve an encounter for your location as normal. Each investigator can resolve a maximum of one terror encounter per round.

To resolve a terror encounter, read the effect based on the total amount of terror tokens in your neighborhood.

• When a neighborhood has 0-2 terror on it, resolve this encounter.
• When a neighborhood has 3-4 terror on it, resolve this encounter.
• When a neighborhood has 5+ terror on it, resolve this encounter.

Terror Card

After you resolve a terror encounter, that card is discarded facedown to the bottom of the terror deck. Then, you may resolve an encounter as normal for your space, resolve an encounter ability (as described later in this booklet), or end your turn for the encounter phase.

Monsters

Under Dark Waves introduces monster keywords that adjust the way some monsters behave. It also adds new rules for the way monsters move around the board during the monster activation step.

Monster Movement and Travel Routes

Monsters treat all travel routes of the same type as being adjacent to each other. When a monster moves toward its destination or prey and there are multiple travel routes it could move to, it follows the shortest path toward its prey or destination.

Monster Keywords

New keywords appear on some monsters and epic monsters in Under Dark Waves. The rules for each keyword are detailed below. Reminder text is often printed where these keywords appear to assist players with a summary of these rules.

Pursuit

After a non-exhausted monster with the "pursuit" keyword is dealt damage by an investigator in a different space, that monster disengages all investigators and moves a number of spaces equal to its speed toward the investigator who dealt that damage. During this movement, the monster does not engage any other investigators. After this movement is complete, the monster engages an investigator in its space.

Relentless

A monster with the "relentless" keyword cannot be exhausted and cannot be dealt damage by an investigator in another space. After you evade a relentless monster and perform your additional action, if you have not left its space, the monster engages you again. A relentless monster can be defeated by an effect that defeats it without dealing damage, even by an investigator in a different space.

Retaliate

After you perform an attack action while engaged with a monster with the "retaliate" keyword, if you dealt no damage to that monster as part of that action, it attacks you.

Attachments

Various effects may attach a card to another component. When a card attaches to a component, tuck it underneath that component so that the effect text is still visible.

Assets that can be attached to another component have the attachment trait. Each attachment may only be attached to a single other component, although multiple attachments may be attached to the same component.

An attachment may grant new ability text to the card to which it is attached, indicated by the word "Attached:" in bold. The attached card is considered to have that additional text, and that text has no effect unless the card is attached. Both cards retain their complete printed text unless an effect states otherwise, and each investigator can use abilities on attachments attached to assets in their own play area. If the attached card is discarded, the attachment is discarded as well. If only the attachment is discarded, the other card is no longer attached and remains in play.

Encounter Abilities

Some components, primarily assets and archive cards, have unique effects that investigators can resolve instead of resolving an encounter. These encounter abilities are labeled "Encounter:" in bold.

When you use an encounter ability, it replaces your normal encounter. If you resolve an encounter ability, you do not resolve an encounter that corresponds to your space that round. You cannot use an encounter ability if some other effect prevents you from resolving an encounter for your space, such as a terror card attached to your neighborhood or an anomaly token in your neighborhood. Additionally, you cannot resolve an encounter ability if you are unable to resolve an encounter, such as while engaged with a monster.

If the encounter ability has a cost that you are unable to pay, you cannot resolve that ability and must resolve an encounter in your space instead.

Like a component action, you may only use an encounter ability on a card that is in the codex or in your own possession.

Some encounter abilities can be resolved only under specific circumstances, such as while in a specific space. These restrictions are described at the end of the encounter ability text.

Archive Cards

Under Dark Waves introduces new ways for archive cards to enter play: as artifacts under the investigators' control or as a randomized investigation deck.

Artifacts

Some archive cards represent artifacts. Artifacts are a specific type of item. They have all attributes that items have, and all rules that apply to items apply to artifacts.

When an artifact would be added to the codex, an investigator gains that artifact instead, as indicated. When an artifact is discarded, return that card to the archive.

Investigation Deck

Effects in some scenarios gather a number of indicated cards from the codex to create the investigation deck. To do so, shuffle those cards without looking at them and place the deck facedown next to the codex.

Other effects may instruct an investigator to draw or discard cards from the investigation deck. When you draw a card from the investigation deck, add it to the codex. When you discard a card from the investigation deck, return it to the archive.

Double-Sided Cards

Some double-sided cards become a different card type when an effect causes them to flip. Such cards indicate the original card type in parentheses on the reverse side.

When such a card enters play, it enters play as the card type that matches the deck it came from, with the appropriate side up, and changes type when an effect causes the card to flip. When such cards are discarded, they are returned to the appropriate deck for the original card type.

Example: The Watcher is in the monster deck, but does not have an engaged side. It enters play ready side up, and when it would engage an investigator, it flips to the condition side and changes type, revealing the effect text, "When The Watcher would engage you, gain this condition instead." The condition side of the card displays that the card type is "Condition (Monster)," indicating that it was originally a monster card. When The Watcher leaves play, it is discarded to the top of the monster deck.

Event Deck

If an effect would cause an investigator to take or discard a card from the event deck when there are no cards in the deck, cancel that entire effect and place one doom on the scenario sheet instead; then, shuffle the event discard to create a new event deck.

Example: Carson Sinclair draws a spawn clue token from the mythos cup when there are no cards remaining in the event deck. He places one doom on the scenario sheet, then shuffles the event discard and places it into the event deck holder. He does not spawn a clue.

Adding a Tile to the Map

During a scenario, effects in the codex may instruct investigators to add tiles to the map. Archive cards with such effects include a map that shows which tiles to add to the board and where to place tokens, monsters, and/or doom.

When the investigators are instructed to add a tile to the map, shuffle the encounter deck for that neighborhood and prepare it as described during setup (described in the Rules Reference, entry 102.4).

Tainted Condition

The new tainted condition represents an investigator becoming infected with the evil of the mythos. Like other condition cards, the tainted condition is double-sided and includes hidden information on the back. Do not look at the back of the card until instructed to do so by a game effect.

Modifying the Mythos Cup

When the investigators are instructed to remove a mythos token from the game, select a token of the appropriate type from those still in the cup, if able. Otherwise, select a token of the appropriate type from those that have been drawn from the cup, but not yet returned to it.

When instructed to add a token to the mythos cup, add it directly to the mythos cup.

Clarifications

Spawn a Clue

Any time an effect spawns a clue, resolve that effect the same way you would resolve a spawn clue mythos token: take the top card of the event deck, place a clue in the indicated neighborhood, and shuffle the card into the top of that neighborhood deck.

Monster Cards

The abilities, keywords, and modifiers of monster cards in play are open knowledge. Investigators may look at either side of any monster cards in play at any time. Investigators may not look at cards in the monster deck.

Effects that Target Assets

Unless an effect specifies a location (such as "an ally in any space" or "an item in your space"), it can target only the assets controlled by the investigator encountering or triggering the effect. An asset controlled by an investigator is in that investigator's space.

Example: Zoey Samaras's enchant weapon spell reads, "Attach this card to a weapon in your space." Zoey and Michael McGlen are both at Falcon Point, so she can attach the spell to his Chicago typewriter or her own chef's knife.

Searching for Specific Traits

When an effect tells you to reveal, spawn, or gain a card with a specific trait, reveal cards from the appropriate deck, one at a time, until you reveal a card with the specified trait and put that card into play as indicated. Shuffle any other cards you revealed this way and return them to the deck from which they came.

For decks that draw from the top of the deck (such as the item deck), reveal cards from the top and return them to the bottom of the deck.

For decks that draw from the bottom of the deck (such as the monster deck), reveal cards from the bottom of the deck and return them to the top of the deck.

Game Modes

Under Dark Waves adds optional game modes to Arkham Horror that allow players to either adjust the difficulty of the game or to link multiple scenarios together into a series of games of escalating difficulty.

Story Mode

This mode reduces the pressure the game places on the investigators and provides more time to react to threats, allowing you more opportunities to explore encounters and experience all that Arkham has to offer.

To play Arkham Horror in story mode, during the "Create Mythos Cup" step of setup, replace one of the doom tokens with a blank token.

Challenge Mode

This mode causes doom to spread more aggressively and forces the investigators to carefully optimize their actions. You will have less time to react to the various threats the game presents, so each action is vitally important.

To play Arkham Horror in challenge mode, during the "Create Mythos Cup" step of setup, replace one of the blank tokens with a doom token.

Inevitable Mode

This mode allows investigators to play a series of sequential games of escalating difficulty. The goal is to complete as many games as possible before the Ancient Ones overwhelm Arkham and lay waste to the world.

After the investigators lose any single game, the inevitable death of the universe has finally caught up to them, and the series is finished.

Inevitable Mode Rules

• The investigators lose the series if they lose any single scenario.
• The investigators win the series if they win every scenario.
• Set up the first scenario of the series in the same way as a standard game, using a random scenario.
• Set up each subsequent scenario by randomly selecting a scenario that has not yet been played in this series. Each scenario can only be played one time in each series.
• Each game may be played with a different number of investigators, and additional expansion material may be added between games.
• Investigators that have been defeated or devoured are removed from the series permanently and cannot be used in later games. They cannot be chosen either during game setup or when selecting a new investigator during the game. Investigators that were retired in a previous game may be used.
• The players lose a scenario, and the series, if a player is unable to select an investigator to play because all available investigators have been defeated or devoured.
• Reset all other components and effects between games.
• At the start of each game, modify the setup as shown below, according to the number of games played in the series. These effects are cumulative.

Game #	Setup Modifier	Setup Step
1	Standard setup.	—
2	Spread doom one additional time during setup.	11.3
3	Remove one blank token from the mythos cup. Add one doom token to the mythos cup.	5
4	Spawn one fewer clue during setup.	11.2
5	Remove one doom token from the mythos cup. Add one gate burst to the mythos cup.	5
6	Resolve one gate burst at the end of setup.	11.5
7	Remove one blank token from the mythos cup. Add one headline token to the mythos cup.	5
8+	For each game after the seventh, place one additional doom on the scenario sheet at the end of setup.

Example: At the start of game three in an inevitable series, the investigators spread doom one extra time during setup and replace one blank token in the mythos cup with a doom token.

Quick Reference

Encounter Icons

Payments	Rewards
Suffer Damage	Move an Investigator
Suffer Horror	Spawn a Clue

Mythos Token

• Spread Terror (spread terror mythos token): Spread terror in the unstable space's neighborhood by placing one terror in that neighborhood and attach one terror card to that neighborhood's encounter deck.

Travel Route Types

• Country Road
• Ferry Terminal
• Train Platform