I don't get the fashion week mode @ all but it sounds fun.
Can you only do it once a week?
It's a sub-mode of Normal mode. Your goal on this mode is to open all clues hidden. Get 'Perfect' judgement and to open 1 clue.
Once you open up 1 clue you'll get +10,000 score. If you open up all fashion part like for example Head. You'll get +10,000 score for opening the clue and additional 50,000 score for finding all clues of that part.