Unfathomable is a strategic cooperative board game that sees its players working together to ensure the safety of the S.S. Atlantica and its passengers on a journey across the ocean to Boston in 1913. However, the pull of the Lovecraft-inspired Deep Ones are strong, and some of the players will eventually turn traitor — causing you and your crew to fight for their lives and to keep the ship afloat.
Set in the Arkham Horror Files universe, Unfathomable features all-new characters, each with their own shady backstory, and takes place prior to the events of the Arkham Horror board game (see it on Amazon). Combining card-based combat, a bit of role-playing, and a touch of deception, Unfathomable offers a rewarding experience for those willing to sit through its often lengthy play sessions.
What’s in the Box
There's a lot of stuff in the box. First up is Unfathomable’s large six-fold game board that features a detailed depiction of the S.S. Atlantica, including both the interior cabins as well as the ship’s deck. A cardboard punchboard features the four resource dials to permanently attach to the game board, as well as 10 character standees, nine Passenger tokens, four Traitor rings, the Travel Track token, Ritual Track token, and Current Player token.
Additionally you’ll find, not one, but two rulebooks. A standard 28-page guide teaching you how to play the game, as well as a separate 24-page Rules Reference book that should be used after you and your group have an understanding of the typical game flow and need to answer more specific questions. On the rear of this reference book is an index that helps you quickly locate answers based on specific keywords.
Below that are 10 illustrated character sheets that detail their inherent abilities and give background lore on who they are and how they wound up on the ship. There are also reference sheets for Players and Traitors, with helpful information about how to navigate the interior of the ship, what you can do during your turn, and how to activate the Deep Ones.
Beyond the reference sheets, you’ll find tokens, a die, and a whole lot of cards of varying sizes and uses. But wait, there’s more! Under a large cardboard flap you’ll find all the monsters including the detailed Mother Hydra, Father Dagon, and 20 smaller Deep Ones figurines.
Rules and How to Play
The goal of Unfathomable is relatively straightforward: you either help the S.S. Atlantica reach Boston safely as the humans to win, or you sabotage the ship’s arrival in a number of different ways to win if you’re revealed to be a Hybrid — those working against the humans. Humans will reach their destination by advancing the Ship token across the Travel track, usually a minimum of five times.
Setting up Unfathomable can take some time, as you need to shuffle and separate all the individual decks, configure the resource dials, create the supply of Deep Ones, passengers, and Traitor rings, place the initial monsters, and create the Chaos deck. Only then can players choose their characters, place their character standee, and draw their starting hand of cards, as well as receive their starting Loyalty card. Thankfully, the instruction manual includes a handy flow chart to ensure everything is done in the proper order and nothing is forgotten.
Turns then proceed starting with the player holding the Current Player Token. Generally, each turn begins by drawing your five Skill cards, designated by your character sheet. These cards consist of Strength, Will, Influence, Observation, and Lore and contain a variety of different abilities that can be used throughout the game, as well as during skill checks. Each card contains a number in the top right corner that indicates how impactful it is when contributed during skill checks.
Once you’ve gotten your hand, you’ll perform two actions. These include moving around the interior cabins and ship deck, attacking Deep Ones in a given space, rescuing passengers from the deck area, trading Skill cards with another player, or using an Action ability — whether from a card in your hand, on your character sheet, or in a given space. As you’d expect, this is the real meat and potatoes of Unfathomable, and where much of the strategy lies.
If you’re a human, you’ll want to work towards advancing the Travel track each turn, as this is your win condition. However, you need to keep the Deep Ones at bay, as well as preserve the ship’s four precious resources: Fuel, Food, Souls, and Sanity. The sheer number of actions available can be overwhelming as not only do you have five cards added to your hand each turn that have unique abilities, but each space has an optional ability, as well as your character sheet, powerful Feat card, and various Item cards your character holds. This is both a blessing and a curse for Unfathomable, but also what gives it a near-infinite amount of replayability and such a high skill ceiling.
If you’ve secretly been dealt a Hybrid loyalty card at the beginning of the game, your goal is to sabotage the humans in a number of different ways. However, since nobody knows you’re a Hybrid, you must work in secret and try to remain undetected. This puts the traitors in a very unique position as they can play as aggressively or passively as they want to stay off the other players’ radars. However, at any point they can also choose to reveal themselves as a traitor, which unlocks powerful new abilities and a separate deck of unique Skill cards to help bring down the ship.
Since Unfathomable is playable for groups of 3-6 players, there can either be one or two Hybrid Loyalty cards in play at the beginning of the game, meaning there may not be any traitors initially. This leads to some interesting early game shenanigans where players are constantly on edge as they have no idea if a traitor is among the group.
After you’ve completed your two actions, you’ll need to draw a Mythos card. This includes a scenario the group must overcome, such as a leaky hull or a food rationing crisis. Most often, players will be required to pass a collective skill check, indicated by a number in the top left corner of the Mythos card, followed by a number of icons that correspond with the Skill cards. Depending on the outcome of the skill check, players will either pass or fail, and must proceed with the outcome.
During the skill check phase, players can choose to contribute any number of cards from their hand. Generally, the human players will want to add cards with matching icons, however, traitors can secretly add cards that aren’t needed. Since everyone is adding cards face down, nobody knows if someone is trying to sabotage the skill check. Two random cards are added in from the Chaos deck, which contains two of each Skill type to add a layer of RNG to each round. The player who drew the Mythos card then adds up the value of all the necessary Skill cards and subtracts the value of those with incorrect icons. If the outcome is more than the required amount, the skill check is passed, and the players can move on.
However, this isn’t the end of the players’ woes. On the bottom right corner of the Mythos card are two more icons. The first icon indicates which Deep Ones must be activated, including Mother Hydra or Father Dagon — the two large Monarch monsters that can really wreak havoc on the ship by flooding it with monsters or damaging portions of the ship. The second icon on the Mythos card represents which track advances — either the Travel track or Ritual track.
The overall goal for the humans is to advance the Travel track a minimum of five times. Each time it reaches the rightmost space, a Waypoint card is drawn that includes a small scenario that must be overcome, such as losing some resources or damaging the ship. At the top of the card is a number: either 2, 3, or 4. The higher the number, the more detrimental the outcome. Once players have amassed a total of six across the Waypoint cards, another round of Loyalty cards are dealt — meaning there’s at least one traitor amongst the group at that point. Once the cards total 12, players only need to advance the Travel track once more to complete the game and emerge victorious.
While it seems relatively straightforward for the humans, there’s plenty of chaos that can come their way to delay their progress by way of the traitors. Hybrids, whether revealed or not, can win the game by depleting one of the four resources completely, damaging six compartments of the ship, or overwhelming the ship with Deep Ones and depleting the total supply of monsters available.
During the various play sessions with my group, we found the long playtime to be quite laborious, with our longest session lasting upwards of four hours. However, as with many board games, the more you play and interact with the various elements, the easier and quicker it becomes. Still, the advertised 2-4 hour playtime is extremely accurate, and may be intimidating for casual players. This is definitely a game that requires all players to remain attentive, or many components can easily go overlooked. That being said, for dedicated groups that take the time to learn all of its intricate systems, Unfathomable proves to be one hell of a ride.