The Esoterrorists 2nd Edition - Rules of Play says:
You are elite investigators combating the plots of the Esoterrorists, a loose affiliation of occult terrorists intent on tearing the fabric of the world. The Esoterrorists introduces the Gunshoe rules system, which revolutionizes investigative scenarios by ensuring that players are never deprived of the crucial clues they need to move the story forward. So equip you characters and screw you thinking head on and get out there in to the shadow world of the occult!