Goal

Eliminate your opponent or be the player with the best castle.

Setup

Shuffle all the cards and deal 2 to each player. Put the remaining cards face down forming the deck.

How to play

Choose a starting player. Then players alternate to play their turn until one is eliminated or all cards have been played. A player turn consists in 3 steps:

• Draw a card (if possible)
• Play a card
• Resolve effects

Draw a card

Player draws a card from the deck adding it to their hand, which is kept hidden. If deck has been depleted, skip this step.

Play a card

Player must play a card from hand on their castle. That card becomes a Castle Piece and can be played face-up or face-down. Cards played face-up have effects resolved immediately in the next step. Cards played face-down don't resolve it's effect until they are revealed by another card effect.

Resolve effects

Once a card is played face-up or becomes face up (is revealed by any effect) its effect is activated and resolved by the card owner. Resolving a card effect is mandatory (unless there are no effective targets), but you may target any Castle Piece, even yours and those in which the effect will be useless.
Revealed cards effects are resolved after all pending effects have been resolved.

The cards

The deck contains only 18 cards:

• Barracks (x1): 3 points - Turn a Castle Piece face-down
• Battlements (x3): 0 points - Cannot be destroyed. If a player has all three Battlements in play faced-up at the end of the game, they are worth 3 points each
• Marketplace (x2): 2 points - Exchange a card from your hand with another player
• Observatory (x1): 3 points - Look at a face-down castle piece, you may turn it face-up
• Princess Spire (x1): 6 points - Cannot be played face-up. If this castle piece is destroyed, you lose the game
• Throne Room (x2): 2 points - Turn a castle piece face-up. That card has no effect this turn (its effect is not triggered)
• Trebuchet (x4): 0 points - Choose and destroy a castle piece. If that card was face-down, turn it face-up (destroyed card's effect is triggered from the discard pile)
• Watchtower (x3): 2 points - Turn up to two castle pieces face-up
• Wizard Tower (x1): 3 points - Look at the top three cards of the deck and re-arrange them in any order

End of the game

The game can end in two manners:

• Destroying your opponent's Princess Spire: you win automatically
• No player has any cards left in hand: to determine their score, players count up their faced-up castle pieces points. Then add 1 point for each faced-down castle piece. The player with the highest score wins. In case of a tie, the player with more faced-down castle pieces wins. If there is still a tie, the player with less castle pieces wins.

Note: Original rules states that, in case of a tie, 'the player who lives in the largest house wins', but it's obviously a joke. The game designer developed later the tie-breakers referenced here.