Based on City of Spies: Estoril 1942, 2491 Planetship reimplements the mechanisms from a city of spies to a new fictional universe filled with rich lore and characters. In this game, each player captains a "planetship" — a world-sized spacecraft that wonders through the galaxy — and you've received a distress signal from the Mothership Alpha, the first and largest planetship of all! Quickly making their way to the signal's co-ordinates, players are confronted with the horrible vision of a now-crumbling planetship on the brink of exploding. This is where the game begins. Each player must send out their finest team of characters to land on various locations of the Mothership Alpha in order to rescue its most valuable crew. Location boards are randomly selected to be used in each round. Control of these will be fought over in each of the four rounds of the game. Players begin the game with the same hand of characters (tiles) and take turns placing these tiles in the open spaces of the various locations on the board. At the end of each round, players check each location to see which player gains the reward for that location. At the end of the fourth round, players total the points of their characters, plus any special game objectives they have completed. Whoever has the most points wins.