The Mysterious Cave is a cave located in the Celestial Keep region of the See the Future downloadable content for Fable II. It is visited during the Hobbe segment of The Costume Party, and contains some of the wisps needed to free the Cursed Knight. A notable feature of the cave includes the Hobbe statues. While wearing the Hobbe Suit, standing in the circle in front of the statue will cause a Hobbe spirit to appear, similar to the spirits summoned by Raise Dead. The spirits are needed to progress through the cave, as they can remove many of the obstacles that block the path. The main entrance to the cave is located beyond the Balverine gate in the central area by the tree and is just past the Dingly Burrow. The rear exit to the cave comes out in one of the crypts in the cemetery next to the ruined keep building.
A chest in the cave contains the Night Blue Dye, and one of the Murgo Statuettes can be found near the entrance.