Things began to fall into place one after another, and when Harry made it back to the common room, he sat up in his bed with his wand providing light for what he intended to do. Activating the Map, Harry watched as Quirrell's deformed name moved through the castle, finally stopping inside the man's office. On one strip of paper, he wrote the name 'Quirinus Quirrell', and on another, he wrote ' Riddle', the name Ollivander had given him. Propping up his wand up on his pillow, Harry placed the two strips together in front of the light shining from it, slowly shifting it from side to side, until the overlapping names resembled the tag on the Map. There was no first name to complete the similarity, but it was undeniable. Two people were in the space of a single dot, but that was not possible, unless...
Breathing heavily, Harry dropped the strips and watched the dot on the map move onto the bed in the room. Archer... is possession possible? He asked, almost not wanting to hear the answer. Not like how you are inside me, but...
It is. The spirit confirmed.
Harry continued to stare at the dot. If this Map was telling the truth, if it could really detect any presence within the walls of Hogwarts, then everyone here was in danger.
Voldemort himself was right in the castle with them.