Skirmish in the Underground Chambers

The attack in the Philosopher's Stone Chambers was a battle that took place on 4 June 1992, during Lord Voldemort's attempt to use Quirinus Quirrell to steal the Philosopher's Stone. It was also Voldemort's second attempt on Harry Potter's life.

During Harry, Ron, and Hermione's time in the chambers they battled through a set of obstacles that most eleven-year-old children would find near impossible, but succeeded anyway. In the last chamber, Harry defeated Voldemort and kept the stone safe.

The battle in the chambers was a defining moment in the Trio's years at Hogwarts School of Witchcraft and Wizardry, as they realised that their lives were never going to be normal and that Lord Voldemort would always make sure no school year would ever be ordinary.

Fluffy


Fluffy was a giant three-headed dog, and Rubeus Hagrid's contribution to the protections put in place for the Philosopher's Stone. In 1992, Quirinus Quirrell enchanted a Harp to put Fluffy to sleep while he searched for the Stone; when the music stopped, Fluffy awoke. Harry Potter, Ron Weasley, and Hermione Granger had to play a flute to put it back to sleep, before they were able to slip through the trap door Fluffy was guarding. Quirrell found out how to get past Fluffy earlier that year by enticing Hagrid into a card game, offering a dragon egg as the stake, and getting him drunk enough to disclose the secret of how to pacify the otherwise vicious dog. After the Philosopher's Stone was destroyed, Hagrid released Fluffy into the Forbidden Forest.

Devil's Snare


The second obstacle within the Chambers was Pomona Sprout's Devil's Snare, placed seemingly to soften a deadfall through the trapdoor guarded by Fluffy. However, as the Devil's Snare is known for strangling its victims to death, and increasing its force of constriction at signs of struggle, Hermione Granger just barely managed to save Harry Potter, Ron Weasley, and herself from death by strangulation, by attacking the plant with Bluebell flames.

Winged keys
The third of the Chambers contained several brooms and was filled with Winged Keys, provided by Professor Filius Flitwick, which, at a distance, appeared to be birds. There was a locked door at the end of the room which was impervious to the Alohomora spell, and could only be opened by identifying and catching the one key among the "flock" that would fit the door's lock. Hermione Granger cleverly deduced that the key that would open the locked door must be an old one, to match the old lock on the door. The only old key was readily identifiable, as Quirinus Quirrell had just used it and bent one of its wings. As soon as Harry Potter, Ron Weasley, and Hermione took off on brooms to catch the winged key, they rest of the keys scattered to make the correct one more difficult to identify again. Harry was, however, able to retrieve the necessary key, which was described as old-fashioned and silver, with bright blue wings, by employing his skills as a Seeker.

Human Chess Game
The fourth obstacle was Minerva McGonagall's — a giant Wizard's Chess set. Ron took command of the game, with Harry, Hermione, and himself replacing certain pieces (a Black bishop, rook and knight respectively), to defeat the opposing team and be allowed to pass. In the end, Ron sacrificed himself to allow Harry to capture the opposing King. At the End-of-Term Feast, following the events of the attack, Albus Dumbledore awarded Ron fifty House points for winning "the best played game of chess that Hogwarts has seen these many years".

Mountain troll
"I do say I have a gift with trolls."

- Quirrell discussing his chamber

When Harry and Hermione arrived at the obstacle set in place by Quirinus Quirrell — a troll — they realised it was already out cold. It was later discovered that Trolls were Quirrell's specialty, which he had also used to create a diversion during the 1991 Hallowe'en feast, in his first attempt at retrieving the Philosopher's Stone.

Potion riddle
Harry and Hermione next arrived at a Severus Snape's potions riddle. The obstacle wasn't magic but logic, a challenge that most wizards would never figure out, as they did not put much stock in logic. Hermione had no trouble deferring the riddle and figured out which potion would help them, but there was only a little bit left. So Harry drank it and Hermione drank another one, which allowed her to leave the chamber safely. She wished Harry good luck and told him he would be alright. Harry went on to the final chamber alone.

The Riddle as follows:

"Danger lies before you, while safety lies behind,

Two of us will help you, whichever you would find,

One among us seven will let you move ahead,

Another will transport the drinker back instead,

Two among our number hold only nettle wine,

Three of us are killers, waiting hidden in line.

Choose, unless you wish to stay here for evermore,

To help you in your choice, we give you these clues four:

First, however slyly the poison tries to hide

You will always find some on nettle wine's left side;

Second, different are those who stand at either end,

But if you would move onwards neither is your friend;

Third, as you see clearly, all are different size,

Neither dwarf nor giant holds death in their insides;

Fourth, the second left and the second on the right

Are twins once you taste them, though different at first sight."

The attack
"Yes, Severus does seem the type, doesn't he? So useful to have him swooping around like an overgrown bat. Next to him, who would suspect p-p-poor, st-stuttering P-Professor Quirrell?"

- Quirrell reveals were his loyalty lies



Harry, then arrived at the obstacle of Albus Dumbledore — the Mirror of Erised. Standing there was Quirinus Quirrell. Harry was shocked — he had expected Snape. Quirrell explained that he tried to kill Harry, while Snape tried to save him. He said that he let the troll in on Hallowe'en. He then tied up Harry and tried to figure out how to get the Stone. Voldemort told him to "Use the boy" Quirrell summoned Harry to tell him what he saw in the Mirror. Harry lied and said it was himself winning the House Cup. An accomplished Legilimens, Voldemort wasn't fooled and told Quirrell to allow him to speak to Harry. Quirrell unravelled his turban to reveal the red-eyed and snake-like face of Tom Marvolo Riddle.



After Harry's refusal to join the Dark Lord, Voldemort ordered Quirrell to kill him, but because of Lily Evans' loving sacrifice ten years earlier, Quirrell couldn't touch him without experiencing debilitating levels of pain, and having his flesh burn. Around that moment, Harry fell unconscious due to his injuries and the pain in his scar. Voldemort left Quirrell's body and fled, abandoning his servant to die. After Voldemort fled, Albus Dumbledore descended into the chambers. After reaching the Philosopher Stone's chamber he found Harry unconscious and rushed to his aid. If Dumbledore had arrived any later Harry would have died.

End of first year


Three days later, Harry woke up in the hospital wing to find Dumbledore standing before him. Dumbledore explained that the Stone had been destroyed and Nicolas Flamel would die. He, then, explained the reason Voldemort, and by extension Quirrell, couldn't touch him.

1995-1996 school year
"Yeah, Quirrell was a great teacher, there was just the minor drawback of him having Lord Voldemort sticking out of the back of his head."

- Harry Potter telling Dolores Umbridge about the attack in the underground chambers



Three years later, while explaining all he'd done to Ron and Hermione, Harry mentioned the Battle in the Philosopher's Stone Chambers. He was later given detention by Dolores Umbridge for saying that Quirrell had been possessed by Voldemort. Then, at the Hog's Head, Neville Longbottom told everyone that Harry saved the Philosopher's Stone. Then, while trying to come to the Department of Mysteries, Ginny Weasley brought up the fact that she was three years older than they were when they first fought Voldemort.

1996-1997 school year
"Quirrell was mediocre [...]"

- Severus Snape's opinion of Quirrell Four years after this battle, at Spinner's End, Bellatrix Lestrange maliciously reminded him that Snape himself had interfered in the events leading up to the Battle in the Philosopher's Stone Chambers. Snape replied that Quirrell was "mediocre", and that he had stopped him simply because he was "unworthy".

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (film)
 * Harry Potter and the Philosopher's Stone (video game)
 * LEGO Harry Potter: Years 1-4
 * Pottermore

Notes and references
Ataque en las Cámaras Subterráneas Сражение за философский камень pt-br;Conflito nas câmaras subterrâneas