In Mysterium, a reworking of the game system present in Tajemnicze Domostwo, one player takes the role of ghost while everyone else represents a medium. To solve the crime, the ghost must first recall (with the aid of the mediums) all of the suspects present on the night of the murder. A number of suspect, location and murder weapon cards are placed on the table, and the ghost randomly assigns one of each of these in secret to a medium. Each hour (i.e., game turn), the ghost hands one or more vision cards face up to each medium, refilling their hand to seven each time they share vision cards. If a majority of the mediums have identified the proper suspect, with ties being broken by the vote of the most clairvoyant medium, then the killer has been identified and the ghost can now rest peacefully. If not, well, perhaps you can try again…