I think it helps if you've beaten the elite four, first of all. Then, keep an eye out for
a TV advertisement, mentioning a sale on at the Lilycove Department Store. Go straight
there and go to the top floor/roof-top. They should sell stuff there, some of which MIGHT
help with covering up the holes in the hideouts. I've never tried this myself, but I saw
it on "supercheats.com", so it's at least worth trying. =o)

IT REALLY WORKS rachhunter
and i know where u can find it it has 3 rooms
first go to the weather institute (down of Fortree cityu will see 4 laders (before the
weather institute) .There u will see 2 squares where u can use surf
u will surf and go down where u will find a tree use secret power at the left side and u
will find it
HOPE IT HELPED