In Mr. Jack, one of the two players represents Jack the Ripper, who will be one of the eight characters on the board. This player knows which character is Mr. Jack, and his goal is to flee from the district as soon as possible (or avoid being accused for eight turns). The other player represents an independent investigator (not represented on the board) who tries to guess the identity of Jack — but he can make only one accusation during the game! (boardgamegeek.com)