In this card game, based on the beloved priest-detective character created by G. K. Chesterton, 2-6 players take the role of the Investigators and try to create a case against a suspect. The game will be issued in a base game, comprised of all the cards (nearly 200), as well as a deluxe edition with a board showing locations for investigation. The deluxe game can be played with the base rule set, or a separate rule set for a different mode of play.
In either version of the game, first a crime scene is established using the Crime, Suspect, and Evidence decks. Then, players will use the Investigation Resources deck to try to acquire their own Evidence cards in order to try to match them to the requisites of the Crime and Suspects' dossier. Evidence is acquired in rounds of a "bidding"-type action against the other players.
Apart from competing to acquire evidence, however, players can also interfere with one another's investigations by deploying Special cards, or by utilizing a special action allowed to their Investigator type. There may also be a traitor in the game, playing as Father Brown's nemesis Flambeau, whose goal is to masquerade as a detective and stop anyone from solving the crime.
There are also risks in some investigations: a player's Investigator might be killed in the line of duty, forcing that player to draw a new Investigator role and start out again back-footed in his or her investigation!
—description from the designer