Sora, Donald and Goofy float down a Rabbit Hole into the house of the White Rabbit, which is a large room with a hall.
The main room, called the Bizarre Room, has a table with "Drink Me" bottles which cause the drinker to grow or shrink in size. The Rabbit's furniture can be folded up into the walls or flattened to change the room's structure, reveal treasures, or open new doors. Different doors into the Bizarre Room cause the gravity to shift, allowing you to explore the walls and ceiling of the room.
Entering the door behind the bed leads to the Queen's Court, outside of her castle in a hedge maze. Here she runs her pointless court sessions, and is where the boss battle against the Card Soldiers is fought.
The Lotus Forest through the opening to the left is a large wood full of giant mushrooms and flowers which ask for potions and other items; one flower can be given a potion to make Sora grow larger. Various items that can be manipulated, depending on Sora's size, such as the stump, the boulder, and the tree in the center of the wood; knocking the nut from the tree and consuming it returns Sora to a shrunken state.
Finally, there is a small area that is the location of the Tea Party Garden, where the Mad Hatter and March Hare's tea party is laid out; the hosts themselves are imprisoned in a portrait on the wall, but sitting the in chairs around the table can grant prizes or penalties. The portrait also changes depending on the prize/penalty.
Introduced in Kingdom Hearts 358/2 Days there is the Hedge Maze, accessed by a new small area which leads to two giant mazes which are sometimes guarded by Card Soldiers.