From the publisher's website:

Players take on the role of one of the power groups in the politics of the planet Arrakis. The game board, which represents the planet, is split into a number of territories, five of which are strongholds. Players move their units from territory to territory, and if two or more players enter the same territory, a battle ensues and the contest is resolved using a hidden bidding system. Victory in the game is achieved by controlling a specified number of strongholds, either alone or in an alliance with other players. In addition to the areas, the game board is divided into radial sections, and the planet's permanent storm moves along those sections, destroying any troops in its path. Each turn, one territory (determined by a card draw) produces a "spice blow", which places an amount of spice in that territory. An auction is held each turn in which players can purchase "treachery cards". These cards contain a variety of uses such as weapons and defenses, which can be used as advantages in resolving battles. Each player has five leader tokens of varying strengths. Leaders are used in combat to supplement the strength of their units. However, each player has a traitor among the other players' leaders, so using leaders can be a risk. Leaders can be killed in combat, but players may use spice to buy dead leaders back from the Bene Tleilaxu tanks.