first, unlock the "?" boxs then go to the boos court yard, with mario, kill the big one
(i'd ground pound it) then go to the thing that falls out, its a house, try to get to the
actic and theres a pic of luigi

then, theres an marry-go-round. there is 4 rooms, with 4 doors and 3 of them take you back
to the first one (to save you time, i'll tell you what ways to take)

from where you start, go trough the door in frount of you, then go left then right, left
again, theres a brigde go across it be fast! go up the platforms the go down the hole!

the boss boo
you'll see a cutsene of mario's refection in the big mirror turn into luigi!
then king boo comes to beat him, you have to ru n behinde him and punch him (or ground
pound him) he'll vanish and his relfection is left, use it to find him and hit him, repet
till death, grab the key, NOW GO AND GET LUIGI,MAN!

SO HURRY UP AND GO GET HIM ALREADY!!!

go to the courtyard with the boos,punch the
bigger boo with the cage inside him,get the
2 stars in big boos haunt,go to the third door
to the right,deafeat big boo,get key