This game casts players in the roles of dukes who are trying to establish duchies along the banks of the Rhine River.

Players hold a hand of cards that correspond to numbered plots on each river bank, and they place knights in open plots for which they hold the corresponding cards. After establishing duchies, players attempt to expand them to include more plots of land, as well as buildings - such as castles, cathedrals, and cities. These buildings both add to the value of a duchy and provide their owners with advantages during game play.

The game ends when, at the end of a turn, any one player has no more knights available. The player with the highest score at the end of the game wins.