Mysterium is a cooperative game of deduction and teamwork for two to seven players. Over the course of the game, one player takes on the role of the ghost and, over the course of a few scant hours, tries to lead the psychics to the correct culprit. Every member of the team will receive numerous visions, but what is the ghost trying to tell you exactly? Can the psychics determine the weapon, location, and killer, or will the criminal pull off the perfect crime?