You can access this room by taking the door on the left on the second floor of the Foyer. The Master Hall is mostly blocked off by a giant spider web (as seen in the picture) due to the spider infestation inside of the Gloomy Manor. Luigi can get into the Parlor with the bottom left door and get into the Bedroom with the middle door. Luigi can also get into the Rafters behind the big spider web by pulling on the rope, but it can only be accessed in mission A-5 "Sticky Situation".
- In Mission A-5, the Master Hall is is one of the rooms that are always covered in spider webs.