Dream Depot is where all dreams in the Mushroom Kingdom go.
The Star Spirits guard the Dream Depot. In the story of Mario Party 5, Bowser attempts to take over the depot and make the inhabitants of the Mushroom Kingdom have the inability to dream. The Star Spirits request Mario and his friends to prevent this from happening. Mario and his friends chase Bowser across six dreams, which is the Toy Dream, Rainbow Dream, Pirate Dream, Undersea Dream, Future Dream and Sweet Dream, before reaching Bowser's dream, Bowser Nightmare.