The Descent into the Chamber

Harry, Ron, and Lockhart slide down the dark, slimy pipe that leads deep beneath Hogwarts, eventually landing in a stone tunnel. They follow the tunnel, which is littered with small animal bones, until they encounter a gigantic, shed snakeskin, confirming the presence of a Basilisk. Lockhart, seizing an opportunity, steals Ron's wand and attempts to cast a Memory Charm on them, but the spell backfires due to Ron's damaged wand, causing a cave-in that separates Harry from Ron and Lockhart. Harry is now alone, forced to continue deeper into the Chamber to face the Basilisk and save Ginny. The separation heightens the tension and sets the stage for Harry's solo confrontation.