Tormented Souls

After obtaining the Sun Necklace, by solving the TV Dial Puzzle (check the Additional Resources Suplementary Guide section for more information on how to solve this puzzle) in Caroline's room and getting the Moon Necklace from the safe inside the Sewer Storage Room, return through the E-2F Office to the Children's Bedroom and use the combined necklace on the plaque of the wall next to the bed. This will open a secret room, which after approaching to it, will get you the trophy.