Harry, Ron, and Hermione believe that Professor Snape is going to try to steal the Philosopher's/Sorcerer's Stone which is hidden in the castle. They attempt to beat him to it. When Ron is injured, Hermione stays with him and Harry continues on to confront Snape. However, Harry finds Professor Quirrell instead. He is standing in front of the Mirror of Erised, which is apparently holding the stone somewhere. Quirrell explains that it was he who had been trying to steal the stone and that Snape had actually been trying to protect it. A voice from under Quirrell's turban instructs him to use Harry to get the stone. When Harry looks into the Mirror, the stone appears in his pocket. The mysterious voice says to Quirrel, "Let me speak to him." Quirrell removes his turban revealing the face of Voldemort on the back of his head; Voldemort had been using Professor Quirrel to stay alive like a paracite. Under Voldemort's orders, Quirrell attempts to take the stone from Harry, choking him. When Quirrel touches Harry, he dissolves into ashes. Voldemort, now without a body, escapes. In the Hogwarts infirmary, Professor Dumbledore explains that when Harry's mother died to save his life, this act left him with a magical protection which saved him from Quirrel and Voldemort. The Philosopher's/Sorcerer's Stone is destroyed, meaning Nicholas Flamel will die. The heroic acts of Harry, Ron, Hermione, and Neville win Gryffindor the Hogwarts House Cup. Hagrid gives Harry a photo album as he leaves home for the summer, although Harry says he's "not going home; Not really."
Demonhunter
Chosen answer: Voldemort is not on his head in Diagon Alley as explained in the books. He attaches himself to Quirrell when he learns that Quirrell was unsuccessful in getting the Philosopher's Stone from the vault, in attempt to keep an eye on him.
But in the movie when they met in Diagon Alley, Quirrel refused a handshake because it would kill him.
It's never explained in the movie that that is why he doesn't shake hands. In the books, hagrid says that Quirrel hasn't been right since he met a few vampires in the black forest.
Ssiscool ★