Majora’s Mask is set in Termina, an alternate reality to Ocarina of Time’s Hyrule, which is to be destroyed along with its inhabitants in three days by a giant falling moon unless the player can save it from imminent doom. The plot’s antagonist is a mischievous imp called the Skull Kid who has stolen a powerful, ancient artifact called Majora’s Mask from an enigmatic traveling mask salesman. The game introduced several novel concepts, revolving around the perpetually repeating three-day cycle and the use of various masks that can transform Link into different beings. As the player progresses through the game, Link also learns to play numerous melodies on his ocarina, which allow him to control the flow of time or open passages to four temple dungeons. Characteristic of the Zelda series, completion of the game involves successfully traversing through several dungeons, each of which contain a number of complex puzzles and enemies. On the Nintendo 64, Majora’s Mask required the Expansion Pak, unlike Ocarina of Time, which provided additional memory for more refined graphics and greater flexibility in generating on-screen characters.