The Mansion of Hidden Souls is a Saturn-exclusive game that follows the events of the first game. The souls of the hidden mansion have asked you to return, because they have recognized that you possess special powers that allow you to see the butterfly manifestations of the souls living there. Something terrible is afoot at the mansion, and you must investigate things and set them right. Along the way you must discover the true purpose of the mansion and its significance in the universe.
The gameplay is similar to the Sega CD version, with an emphasis on FMV sequences and puzzle-solving. You move from location to location via video sequences, solving puzzles to progress through the story. The game requires patience and attention to detail as you navigate the mansion's secrets.