The aim of playing Call of Cthulhu is to have fun with your friends as you explore and create a Lovecraftian story. One player takes the role of game moderator, known as the Keeper of Arcane Lore (“Keeper” for short), and his or her role within the rules is to run the game for the rest of the players. The rest of the players take the part of intrepid Investigators of the Unknown (“investigators”), attempting to seek out, understand and eventually confront the horrors, mysteries and secrets of the Cthulhu Mythos. The Keeper picks a story to run. These stories are known as “scenarios”, and you will find two at the back of this book. A scenario provides the Keeper with the structure of a story for him or her to present to the players. The Keeper’s role is a little like that of a director making a film in which the actors don’t know how the story will develop. To extend that analogy, the players are like actors who have the freedom to improvise their own scripts.