The Unknowable Room

Harry repeatedly tries to enter the Room of Requirement to spy on Malfoy, but fails because he does not know what Malfoy is using it for. He encounters Tonks, who seems depressed and is looking for Dumbledore. Harry also has a tense Defense Against the Dark Arts lesson with Snape, who mocks Ron's inability to Apparate. Later, Harry and Ron discuss Malfoy's activities. Harry realizes that Malfoy is using Polyjuice Potion to disguise Crabbe and Goyle as other students to act as lookouts. He is determined to find a way into the room, but Hermione advises him to focus on getting the memory from Slughorn instead.