La Chasse au Vampire

In a random place in Eastern Europe, travelers are gathering to fight the evil vampire. There is a day/night cycle determined by a sand glass. In daylight, travelers move twice as fight as the vampire. During nighttime, it is the opposite. The players must bring all 4 artifacts into the vampire lair to kill him and win... but they do not know which artifacts they carry until they reach the crypt, or when they are bitten by the vampire. But some artifacts are actually vampire cards, than can turn a traveler into a vampire, unless he gets a blood transfusion by a fellow traveler who has a compatible blood group ! The vampire wins if he can turn all travelers into vampires.