Arkham Horror 2nd Edition: Lurker at the Threshold Expansion

Lurker at the Threshold Expansion components


Lurker at the Threshold is the seventh expansion for Arkham Horror 2nd Edition, and was released in July 2010. It is a “small box” expansion, meaning that it does not include a new game board. What it does include are 56 Investigator Cards, 110 Ancient One Cards, 18 new Gate tokens (which replace those normally used), and some new mechanics.

Author’s Note: This article is based on the Author’s analysis of the game rules and components. A .pdf of the original rulebook is available from the publisher here.

Named for the August Derleth novel (itself based on about 1500 words-worth of Lovecraft fragments) the Lurker expansion also includes a new Herald, the eponymous Lurker at the Threshold. Introduced in The King in Yellow expansion, a Herald is a demipotent supernatural being that paves the way for the Awakening of the Ancient One by implementing a complex new game mechanic that ultimately impedes the Investigators.

In this case, the Herald is the Lurker at the Threshold— The All-in-One and One-in-All— and it makes Dark Pacts with the Investigators, trading Power for their Stamina and Sanity, but at the cost of dire Reckonings. (While both of the honorifics used for the Herald are traditionally associated with Yog Sothoth, the Herald is not explicitly identified as Yog Sothoth… most likely because Yog Sothoth is already one of the Ancient Ones in the core game.)


There are multiple components in this expansion that can be implemented independently or in combination.

New Core-Set-type cards

A Gate Burst occurs at The Witch House, taking the Professor by surprise
A Gate Burst occurs at The Witch House, taking the Professor by surprise

This is the easiest implementation; it involves no new rules (unless Gate Bursts are used). The big increase in Location Encounters alone is worth using this part of the Expansion.

Notable benefits: provides 57% more Location Encounters, 33% more Mythos cards, and 49% more Gate cards, plus a few new Items and Spells.

Further, as the Lurker Mythos cards include the Gate Burst mechanism that was introduced in the Dunwich Horror Expansion, the Gate Burst rules can optionally be used as well.

Notable benefits: complicates the easiest route to victory (sealing six gates) by allowing sealed gates at certain locations (the most common gate spawns, of course) to occasionally re-open.

Implementation: During Setup, shuffle the following cards from Lurker into the respective Core Set decks:

  • 4 Common Item cards
  • 4 Unique Item cards
  • 12 Spell cards
  • 36 Location cards
  • 24 Gate cards
  • 22 Mythos cards

New Gate markers/rules

A Gate moves into the Southside Streets, pulling Jenny and Joe into Another Dimension
A Gate moves into the Southside Streets, pulling Jenny and Joe into Another Dimension

Lurker includes 18 Gate markers that replace the Gate markers from the Core Set, as well as those from the Dunwich Horror and Kingsport Horror expansions, and provides some new rules for those Gates: essentially, there are different “types” of gates, which exhibit different behaviors.

Implementation: During Setup, replace core set Gate markers with the corresponding Lurker Gate markers. Do the same for Dunwich Horror and/or Kingsport Horror Gate markers if using those expansions.

Notable benefits: adds thematic, game-altering complexity to the vanilla core set Gate behavior. The Moving Gates, in particular, really increase the difficulty of the game; where you can normally leave a Gate open in the short-term to prevent more Gates from opening at that location, a Moving Gate can (and eventually will) move into the streets, unblocking the location where it first opened. Worse, a Gate in a Streets space cannot be Sealed, it can only be Closed, so it cannot count towards the easiest victory condition (seal 6 gates).

Relationship cards

The Relationship cards

Lurker includes 12 unique Relationship cards, which is a new type of card. Relationship cards are similar to Skill cards, except that each one is shared between two characters: a given Relationship card can be utilized both by the character that possesses it and the character to their left.

Implementation: During Setup of games with two or more characters, shuffle the Relationship card deck. If there are only two characters, only the character selected as First Player receives a Relationship card; if there are three or more characters, each character receives a Relationship card. Relationship cards are only received during Setup; characters entering the game later (as after a Devourment) do not receive Relationship cards.

Notable benefits: makes the characters just a bit more powerful by giving them a few more Skill-type bonuses in a way that reinforces the cooperative nature of the game. Provides more opportunities for role-playing by characterizing the interpersonal relationships of the individual Investigators.

The Herald: The Lurker at the Threshold

Herald card, Dark Pact cards, Reckoning cards and Power tokens

This component of the Expansion is by far the most complex.

The Lurker at the Threshold is a cosmic Herald that has come to Arkham to pave the way for the Awakening of the Ancient One. Players can make Pacts with the Herald that variously allow them to bind an Ally to their service, to convert Stamina and Sanity to Power tokens, and to convert Power tokens to Stamina, Sanity, Clues and Money. There are three types of Pact; each character can have up to one of each type.

The downside to trafficking with the Herald comes in the form of Reckoning cards, which are drawn each time a Gate opens; 23 of the 28 cards in this new deck are harmful… and one of the “beneficial” cards can draw even those with no Pacts into the Herald’s ever-tightening web of malevolence.

Even the devout may find it necessary to make unpalatable deals with the Herald, accepting a Pact in exchange for the free, successful casting of a critical Spell, when everything rides on the result. Accepting this sort of help from the Herald is particularly perilous, though, as it requires the Player draw a Reckoning card as well as taking a Pact card.

And should the Ancient One awaken, some Pacts will vastly complicate its defeat.

Implementation: During Setup, place the Lurker at the Threshold sheet next to the Ancient One sheet. Separate the Dark Pact cards by Pact type and place them with the rest of the Special cards from the Investigator decks. Shuffle the Reckoning deck and place it next to the other Ancient One decks.

Notable benefits: provides significant new resource conversion options, and thus more tactical flexibility, but at a potentially dire cost. This part of the Expansion is nicely thematic, contributing to role-playing opportunities, and the Reckonings effectively ratchet up the tension.

Player Aids

I have updated the player aids that I created for use with the core game wherever implementing one or more components of Lurker would change them. If there is not a Lurker update to a particular player aid, you can use the version for the core game.

  • Setup
    Covers the game setup process, including special cases and determination of all in-game limits/triggers, plus optional steps to set up the various Lurker components.
  • Order of Play
    Detailed order of play document that covers all five phases of the game turn, including all situational rules, special cases and checks for limits/triggers. Includes optional rules for the various Lurker components.
  • Combat
    Covers the combat process, including all situational rules, special cases and Monster Abilities, as well as resulting Unconsciousness and Insanity. Includes optional rules for the various Lurker components.
  • DM Notes
    More detailed handling of monster spawns, gate spawns, the Terror Track and character Devourment. Includes optional rules for the various Lurker components.
  • Location Encounters
    This is a summary of the Location Encounter cards, listed by Location. It includes the ratio of “good” cards to “bad” cards (a measure of how risky the Location is), which skill checks might be required (and how likely each is), and a list of the best (for “good” cards) or worst (for “bad” cards) possible results. Updated to include Location Encounter cards from the Lurker expansion.
    arkham_horror_lurker_loc_ enc.pdf
  • Mythos Cards
    This is a statistical summary of the Mythos cards, with the data presented by Location. For each, it lists the chance of a Gate opening each time a Mythos card is drawn, the chance of a Clue spawning each time a Mythos card is drawn, and the ratio of the two, which indicates the safest, most Clue-productive Locations as regards Mythos cards (Gates and Clues can spawn for reasons other than Mythos cards). Updated to include the Mythos cards from the Lurker expansion, and to list the chance of an attempted gate spawn at a Sealed location causing a Gate Burst.

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