 The current version is based on the "Unisystem", but previous versions have used "GURPS" and its own system.A secret American government agency called AEGIS has been aware since the Roswell Incident of 1947 that there is an extraterrestrial presence on Earth, characterized by supernatural and paranormal phenomena.Player characters take the role of AEGIS operatives, usually disaffected government agents employed by real-world organizations such as the FBI or ATF or an organization created for the game, such as the Defense Tactical Information Center or Project Rasputin.