 The Thousand @-@ Year Door is not set in the Mushroom Kingdom , but in a cursed land across an unnamed ocean far away . The majority of locations are not featured in previous Mario games . Most locations consist of a set theme ; <unk> , for example , is a floating city centered around a fighting arena known as the <unk> Pit . The enemies and town inhabitants in the game range from recurring Mario characters , like Boo , to characters exclusive to the game , such as the X @-@ Nauts . For many stages in the game , the story is presented in the context of a novel , and is divided into eight chapters ( nine counting the prologue ) . 
