Chapter 17 - "The Man With Two Faces" - In which Harry discovers that it is Quirrell who is after the Stone and serving Voldemort, not Snape. Quirrell tries to use the Mirror of Erised to find the Stone but the Mirror gives it Harry. Voldemort realizes this and as part of Quirrell orders the professor to kill Harry, who blacks out during the struggle. He awakes in a hospital bed and hears many things from Dumbledore. At the end of term banquet, Gryffindor is awarded the House Cup.

Going After the Stone
In the next room, Ron realizes they'll have to play a giant game of [Wizards' Chess] to get through, and takes charge - sacrificing himself to win the game and let Harry and Hermione continue on.
Harry and Hermione encounter a logic puzzle with [potions]. Hermione solves it and she and Harry drink the correct porions so Harry can proceed and Hermione can return for help, and Harry walks through the door.
The Final Confrontation
In the final [chamber], Harry encounters not Snape, but Professor Quirrell, in front of the Mirror of Erised. Quirrell proceeds to tell Harry about his attempts to kill him, and Snape's protecting Harry. But when he turns his attention back to the mirror, he cannot figure out how to get the Philosopher's Stone.
Harry hears a voice directing Quirrell, who orders him to stand in front of the Mirror of Erised. When he does, he gets the Philosopher's Stone, and Quirrell unwraps his turban to reveal Voldemort. But when Voldemort orders Quirrell to kill Harry, he cannot but instead is sent into terrible pain. Harry is then wrenched away from Quirrell and blacks out. Somebody please rewrite this so it doesn't suck.
In the Hospital Wing
Harry awakes in the hospital wing, where [Albus Dumbledore] tells him about Voldemort, the Philosopher's Stone, and Snape's life debt to James Potter.
After much begging, Harry convinces Madam Pomfrey to let Ron and Hermione in to visit him, and he tells them all about his encounter with Voldemort.
Just before he heads downstairs for the leaving feast, Harry is visited in the hospital wing by a weeping Hagrid, who apologizes for his part in putting Harry in harm's way, and gives Harry a photo album with pictures of his [parents].
The Ending Feast
At the end-of-year feast, [Dumbledore] awards 170 points to Gryffindor for their part in saving the Philosopher's Stone, giving them the [House Cup].
The year ends and Harry, Ron, and Hermione take the Hogwarts Express back to [London]. There [Uncle Vernon] is waiting to take Harry home, as unpleasant as ever, but Harry heads off anyway after a last goodbye with Ron and Hermione.