Slytherin common room
The Slytherin common room is the underground headquarters of Slytherin House at Hogwarts School of Witchcraft and Wizardry, a long, low chamber with rough stone walls and ceiling from which round, greenish lamps hang on chains. A fire crackles under an elaborately carved mantelpiece, and several high-backed chairs are silhouetted around it. It is the only place in the castle that Harry Potter and Ron Weasley ever infiltrate, and they do so only by transforming themselves into Vincent Crabbe and Gregory Goyle with Polyjuice Potion, making the room the site of a rare, disguised glimpse into the enemy House's inner sanctum.
Location and Appearance
The Slytherin common room is reached through a stone door concealed in a stretch of bare, damp wall in the labyrinthine passages deep under the school, accessible only by speaking the current password. When Draco Malfoy leads the disguised Harry and Ron to it, he pauses by the wall and says, "What's the new password again?" before answering his own question with "pure-blood," causing the door to slide open. The room itself is a long, low underground space with rough stone walls and ceiling, lit by round, greenish lamps hanging on chains. A fire crackles under an elaborately carved mantelpiece ahead, and several Slytherins are silhouetted around it in high-backed chairs. The atmosphere is one of dim, subterranean comfort, a deliberate contrast to the bright, warm Gryffindor common room.
The Polyjuice Infiltration
On Christmas night, Harry and Ron, having transformed into Goyle and Crabbe respectively, follow Malfoy into the common room after he finds them wandering the dungeons. Malfoy, believing he is speaking to his two cronies, leads them to a pair of empty chairs set back from the fire and tells them to wait while he fetches something his father has just sent him. He returns with a newspaper clipping from the Daily Prophet reporting that Arthur Weasley, Head of the Misuse of Muggle Artifacts Office, was fined fifty Galleons for bewitching a Muggle car, and that Lucius Malfoy, a governor of Hogwarts, called for Weasley's resignation. Malfoy gloats over the clipping, mocking the Weasleys' poverty and their love of Muggles, and performs a cruel impression of Colin Creevey begging Harry for his picture and autograph. When Ron, as Crabbe, reacts with fury, Malfoy snaps at him, and the conversation turns to the attacks. Malfoy reveals that he does not know who is behind them, saying, "I wish I knew who it is... I could help them," and that his father refuses to tell him anything about the last time the Chamber was opened, fifty years ago, though he knows that a Mudblood died then. He expresses hope that Hermione Granger will be the next victim. Crucially, he lets slip that the Ministry of Magic raided his manor the previous week, but that his father's valuable Dark Arts items were hidden in "our own secret chamber under the drawing-room floor." This is the key intelligence Harry and Ron sought, though they are forced to flee when their hour of transformation expires and they begin reverting to themselves mid-conversation.
Significance and Aftermath
The Slytherin common room visit proves that Draco Malfoy is not the Heir of Slytherin, despite his family's pure-blood ideology and his father's dark past. It also provides the first concrete evidence that Lucius Malfoy possesses hidden Dark Arts materials, a fact Ron resolves to report to his father. The room's password, "pure-blood," encapsulates the House's founding ideology of blood purity, which the narrative consistently critiques. The infiltration is a rare moment of direct access to the enemy's private space, and the information gleaned there — that the Chamber was opened before and that a Mudblood died — becomes part of the puzzle Harry and Ron piece together with Hermione's help. The room itself, with its concealed entrance and password protection, embodies the secrecy and exclusivity of Slytherin House, standing in stark contrast to the open, welcoming Gryffindor common room that Harry and Ron call home.
