One day, Princess Toadstool, or Peach, is on a trip to Rogueport, the town of pirates, thieves, and other assorted criminals. Peach's trusted caretaker Toadsworth is, of course, making sure she stays out of trouble - but he is also not letting her have any fun. So she sneaks away while he is not looking and a street vendor catches her eye. The mysterious vendor tells her that he has a box that only a purehearted person can open, and inside is the key to vast treasure. Peach succeeds in opening the box, which contains a map. She sends the map and a letter to Mario...but by the time he gets to Rogueport, Peach is gone. Mario begins to search for her, and eventually discovers that the map can lead to the seven Crystal Stars - the mystical keys to opening a door deep within the Rogueport underground that is said to lead to the greatest treasure in the world. This door is the Thousand-Year Door. Mario sets off to gather the stars and find Peach. Along the way, he meets new friends and makes new enemies - all in his quest to open the Thousand-Year Door.