Alternative reality games (ARGs) are interactive narratives that use transmedia storytelling across multiple platforms. They emerged in the late 1990s and were pioneered by games like The Beast, which promoted the film A.I. and involved thousands of players worldwide solving puzzles. ARGs are characterized by collaborative storytelling where players work together online to advance an immersive narrative in real time. Successful ARGs require subtle clues and realistic fictional worlds that blur the lines between game and reality.