I FOUND THE KEY THAT I SHOULD HAVE FOUND IN THE FIRST PLACE! WOHOO!! PROGRESS.
White Day Plot summary: The story of a young man's trip into school at the dead of night to deliver some candy in preparation for the Eastern Holiday of the same name, White Day (the South Korean/Japanese equivalent of Valentine's Day) to 'So-yeong', a girl at school he likes, and to return the diary she left behind. Finding himself locked up soon after entering, escaping the school now becomes a nightmare... Play the game here: http://www.moddb.com/games/white-day
