Get ready for a seance like no other in Mysterium, a cooperative deduction game that puts you in the shoes of psychics trying to unravel an ancient crime! The story begins in 1920s Scotland, when astrologer Mr. MacDowell moves into a new house and immediately senses a supernatural presence. He summons the greatest mediums of the era for an extraordinary seance, and you, as these mediums, have just seven hours to connect with the ghost and decipher its clues to solve a forgotten mystery. The ghost, suffering from amnesia and unable to speak, communicates through enigmatic visions, represented by illustrated cards. Your mission is to interpret these images to help the ghost recall the details of its murder: who was the culprit, where the crime took place, and what weapon was used. The more you cooperate and guess correctly, the easier it will be to identify the true killer. Mysterium is a reimagining of the game system from Tajemnicze Domostwo, where one player takes on the role of the ghost and the others are the mediums. To solve the crime, the ghost must first recall (with the help of the mediums) all the suspects present on the night of the murder. Suspect, location, and weapon cards are laid out on the table, and the ghost secretly assigns one of each to each medium. Each hour (or round), the ghost deals one or more face-up vision cards to each medium, refilling their hand to seven cards after each distribution. These vision cards present dreamlike images to the mediums, with each medium first needing to deduce which suspect corresponds to the received vision cards. After the ghost has dealt cards to the final medium, a two-minute sand timer begins. Once a medium has placed their token on a suspect, they can also use clairvoyancy tokens to agree or disagree with other mediums' guesses. When time runs out, the ghost reveals whether the guesses were correct. Mediums who guessed correctly move on to guess the crime's location (and then the murder weapon), while those who didn't keep their vision cards and receive new ones next hour, corresponding to the same suspect. Once a medium has correctly guessed the suspect, location, and weapon, they move their token to the epilogue board and receive one clairvoyancy point for each hour remaining. They can still use their remaining clairvoyancy tokens to score additional points. If one or more mediums fail to identify their proper suspect, location, and weapon before the end of the seventh hour, the ghost has failed and dissipates, leaving the mystery unsolved. If, however, they have all succeeded, the ghost has recovered enough memory to identify the culprit. Mediums then group their suspect, location, and weapon cards on the table and assign a number to each group. The ghost then selects one group, places the matching culprit number face down on the epilogue board, picks three vision cards (one for the suspect, one for the location, and one for the weapon), and shuffles these cards. Players who have achieved few clairvoyancy points flip over one vision card at random, then secretly vote on which suspect they think is guilty; players with more points then flip over a second vision card and vote; then those with the most points see the final card and vote. 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…