Words Get in the Way
by Darren Rigby
ANSWER: THE SCARLET PIMPERNEL
The PDF is a text of the then current state of the MIT Mystery Hunt wikipedia page. However, it has one extra word added to it: steganography.
In the PDF are various letters of reduced size that spell the message YOU CANT SEE WHATS WRONG WITH ME. Copying and pasting the text of the PDF to a Unicode-compliant text editor or word processor reveals that some of the characters are not what they appear to be: glyphs from the basic Latin character set have been mapped to other characters. The correct encodings reveal themselves when copied since the special font used to create the PDF is not installed on solvers' computers.
The affected words are shown below (as is a screenshot for those without Unicode character sets):
The letters in their correct encodings resemble Latin characters that spell out THE SCARLET PIMPERNEL.