The barons are trying to impress each other and the king by building beautiful castles. When you place tiles to your castle, your baron moves around a path to collect bonuses, and the first to reach 7 coins wins the game. Build high to move more, and add features like windows and tiled roofs to gain even more bonuses along the way.
On your turn, you either draw 2 tiles to your tile holder ('hand'), or you build a tile to your castle, either from your hand or from the shared market. Depending on what tile you build and where, your baron gets to move a certain number of steps. If you land on an opponent, you pass it for free! If you land on a bonus, you collect it, and if you land on or pass a coin bonus, you take a coin from the coin market. Each coin has an immediate 1-time effect, and the first to reach 7 coins wins the game. An example of a coin effect can be: 'The player with most windows on the castle draws 2 tiles'. This enhances competition and the importance of timing.
When building, your tile number must be the sum of the 2 tiles it is built on, rewarding careful planning. +-1 adjustments can be paid for. Some tiles can be placed on any number, but often limit how you can continue upwards.
