hellp

you go to boos garden (the garden with the gohsts) and attack the biggest boo ( a boo is a
gohst) then a cage looking thing will jump out after you attack the biggest boo. go in the
cage and complete the first mission then on the second mission when you defeat king boo go
up the stairs (skip the star) and find the room with all of the book cases that get thrown
at you in that room somewhere there will be a ? box be mario and fly up above you and you
should see a painting of luigi go in it and you will hear laughs follow the laugh untill
you jump down a hole then you should be in a room with a large mirror you will have to
defeat the king boo in that room but when you first get in there go up to the mirrior and
just look in it untill luigi shows up on the other side of the mirror :)
hope i helped...