Prologue

The adventure begins when Princess Peach goes on a cruise to Rogueport where she meets a hooded woman, and buys a box which contains a map, which the princess sends to Mario, along with a letter asking him to help her search for the map's treasure. Soon after that, she is kidnapped by Sir Grodus. Mario receives the letter with the map and decides to help her, and thus boards a ship to Rogueport.

Shortly after Mario reaches Rogueport, he finds Lord Crump attempting to interrogate Goombella about the Crystal Stars. Mario intervenes and Lord Crump tries to defeat him. After defeating the X-Naut general and escaping from the X-Nauts, Goombella introduces herself, and Mario explains his quest to her. As Goombella is also searching for the map's treasure, she decides to join Mario. Then, Goombella suggests to go to Professor Frankly's house, to consult him and show him the map. At the professor's house, Frankly explains that the map is related to the legend of the treasure of the Thousand-Year Door, and that, to obtain the treasure, one must first open the door with the seven Crystal Stars. Said objects can be found by holding the Magical Map before the Thousand-Year Door, which is located in the town's sewers. So, Mario holds the map before the Thousand-Year Door, revealing the location of the first Crystal Star.