From the Super Mario Wiki
The Master Bedroom (known as Bed room 1 in a pre-release version) is a room in the first area of Luigi's Mansion. Luigi captures Lydia, one of the portrait ghosts, in this room. After sucking Lydia in, Luigi receives the Key to the Nursery.
The Master Bedroom is noticeable in that it is one of only two rooms with a ceiling fan, the other being the Billiards Room. Also in the room are Lydia's vanity, a cabinet, a nightstand, a bed, and a plant Luigi can water for a Green Jewel. From the window, one can see the Toad on the Balcony.
Ghosts in the Master Bedroom
Ghosts in The Master Bedroom during the blackout
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