The Mysterious Tower

Mysterious Tower (不思議な塔) is a world in Kingdom Hearts II and Kingdom Hearts Birth by Sleep. It serves as a starting point for Sora's second quest.

Outside the Tower
The Tower resides in a secret area of Twilight Town, accessible only by a special train that only appears sometimes in the Central Station. The Countryside itself consists of several hills apparently floating amongst the clouds in the endless sunset of Twilight Town, with several stars gleaming in the background. Other than the hills and the tower itself, the only physical existence in the Countryside is a glowing railway along which the single train rides.

The Tower itself is a surrealistic, crooked, golden-brown tower, loosely based on the setting of Fantasia's The Sorcerer's Apprentice. Though it appears to be missing several key structures from the movie, such as the well and the basement study, it appears that the segment is canon to the Kingdom Hearts storyline, and this tower is where it takes place.

The Tower is topped with blue cone-shaped turret roofs, decorated with moons and stars, similar to Yen Sid's hat. It rests on a floating island that contains a courtyard and many trees that obscure the rest of the Countryside from view.

Inside the Tower
Inside the main door is a simple round room, surrounded by an upward-spiraling staircase that leads to a strange portal. Through the portal, a person is transported to higher areas of the Tower, where the staircases float randomly. They lead into other portals or doors to other parts of the Tower.

Other than the entrance, stairs, and upper floor, there are two known rooms in the Tower. One is the Moon Chamber, and the other is the Star Chamber. Both are perfectly round rooms, each with two doors leading either up or down the Tower, and are decorated with moons and stars, respectively. The final stairway is steep and straight, and leads to Yen Sid's Study.

Yen Sid's study is the largest room in the building, with several shelves containing many books, several about the exploits of King Mickey. There is a large wooden desk behind which Yen Sid sits, and behind it, large star and moon windows displaying the Countryside. A door on the side of the study gives way to another room where the three fairies, Flora, Fauna, and Merryweather, apparently stay. There is also a large wardrobe, and several covered mirrors that display Sora in his drive forms, including Anti Form and Final Form.

Kingdom Hearts Birth by Sleep
During Kingdom Hearts Birth by Sleep, the Jump Festa 2008 trailer shows Mickey training with the Star Seeker Keyblade in Yen Sid's study while Donald and Goofy look on; it is known that they guard the tower. At one point, they find Ventus unconscious after hearing an explosion, clutching a translucent, blue paopu fruit-like object in his hand. It is unknown whether it is the same tower in Twilight Town or a different tower in a different place with a similar inside, as in Kingdom Hearts II, Goofy and Donald are unaware that Yen Sid lives in the tower in Twilight Town until Pete tells them.

Scans have shown Ventus to stand with Donald and Goofy at one point in his storyline, Terra speaking with Yen Sid and also encountering a training Mickey.

Kingdom Hearts II
After Sora awakens from his year-long sleep in the basement of the Old Mansion, he meets briefly with King Mickey, who gives him munny and tells him to take the mysterious train to Yen Sid. After being seen off by Hayner, Pence, and Olette, the three take the train and arrive at the base of the tower.

Getting off the train, the trio meet Pete, who is loitering outside after sending in Heartless to attack the Tower's master. After hearing who lives in the Tower, the three hurry inside to meet the King's tutor, leaving a bewildered Pete behind. They make their way to the top, slaying Heartless on their way up, and eventually reach Yen Sid. The sorcerer gives them a book that summarizes all three games, and gives them information about the Nobodies and Organization XIII. He and the good fairies also give Sora his new outfit and drive form abilities, and returns the lost Gummi Ship to Donald and Goofy.

After the party leaves, Diablo, Maleficent's Raven, arrives with Maleficent's robe that was left in Hollow Bastion. The three good fairies recognize it immediately, and their memories of its owner start to work magic on it and bring Maleficent back to life. She plotted to take over the Tower and announced her return with her trademark laugh.

It appears, though, that she failed, as she instead began targeting other castles all over for the same reason, and later, when the player can return to the Tower, there is no evidence that she ever held any sway over it. However, Yen Sid and the Good Fairies are completely absent, and the Tower is overrun by lesser Nobodies.

Trivia

 * Although it is seen as a part of Twilight Town, it is considered as a separate world story-wise . This is mentioned in an interview included in the Secret Report book released with Kingdom Hearts II Final Mix+.
 * When the party first arrives at the tower in Kingdom Hearts II, Donald and Goofy seem shocked that the tower is Yen Sid's, yet in a trailer for Kingdom Hearts Birth by Sleep they are shown to be watching Mickey train under Yen Sid. However, it is possible the outside can change appearance through magic to suit Yen Sid's needs. It is also possible that Yen Sid has several towers with different appearances.
 * If Donald and Goofy have previously visited the tower, it seems likely that one can reach the tower without taking the train from Twilight Town as they would have recognized the area if they had been before.
 * If you visit it later, no one is there. The entire tower is empty, except for Nobodies. If you didn't read the book in the beginning, you can read it now.