Obtained: Located in the Old Sorceress' Mansion - Hallway, the Celestial Plate is hidden behind a broken-down marble statue. To recover it, make sure to push the white marble statue in the left wing of Past within the Mirror as far to the right as possible. Return to the Old Mansion and head back into the left wing in order to retrieve the item. Used for: Placed in the "South" slot in the floor pattern in front of the gate to the Old Sorceress' Hermitage