Weir's Wager is the game of Drunken Tarot, which the Fool plays against the Mistress. It is played with a deck that consists of the enitre Cups suit of the Minor Arcana, five cards of the Major Acana (the Fool, the High Priestess, the Hermit, the hanged Man, and the Star), the Prince, the Book of Thoth, as well as mirrored images of the aforementioned cards. There are also seven Elixir cards, which affect the play of the game.
The object of the game is to win by getting 999 points before the Mistress does.
The layout of the screen shows fourteen cards. The two cards in the lower left corner are the Mistress' cards, and the two cards in the lower right are yours. The four cards on the bottom are community cards. On each turn, each player gets a chance to swap the order of their cards as much as needed before swapping one of their cards with one of the ten community cards, in order to form a winning hand. Once a community card is placed in a hand, a new card takes the place where the community card originally was, and the opponent gets a turn. Play goes back and forth until a winning hand is made. Once a winning hand is made, new cards are dealt for the next round.
What determines a winning hand are the rules as defined by the Elixir card. There will always be one Elixir card in the community cards. It will only change once it is made into a hand, or after a set amount of turns played. The Elixir cards and their corresponding rules are:
Relax - Ascending (Arcana to Cups)
Calm - Ascending (Cups to Arcana)
Rest - Descending (Arcana to Cups)
Heal - Descending (Cups to Arcana)
Relief - Mirror (All)
Soothe - Mirror (Arcana to Cups)
Repose - Mirror (Cups to Arcana)
Hands are scored by making sets, runs or pairs, depending upon the current rules, which are determined by the current Elixir.
Runs are made by two cards in a row in the Cups suit. There are no substitution cards, but mirrored Cups cards count the same as their counterpart (e.g. 'Cups of Five' counts just like the regular 'Five of Cups'). Ascending Runs are made with the lower card on top, and Descending Runs are made with the higher card on top. You can have 'False' versions of the runs by using two mirror cards, or a 'Mixed' version by using one mirror card and a regular card.
Pairs count when the round calls for "Mirror". In that case you must make a pair with a card and its mirror image (e.g. 'the Prince' and 'Prince the'). "False Mirrors" are made when the mirror card is on top instead.
Sets count in any round. Sets are only made with the Elixir card as the player's top card, and a specific non-suit card as the bottom. Mirror images also count. If such a set is successfully made, a new Elixir card will be dealt, meaning the next round's rules will change. An unsuccessful attempt at a set results in 'poisoning', which will cost you points. In a set, the Elixir card must always be the top card. The points scored for each hand also vary, depending upon if the round is 'Arcana to Cups' or 'Cups to Arcana'. In the first case, Arcana hands are worth a bit more, whereas in the second case, the Cups hands are worth more.