Ron and Harry speculate about ways to enter Moaning Myrtle's bathroom and question her about her death. With no good ideas, they head to class, only to be informed by Professor McGonagall that exams would take place in a week. Nobody has studied, of course, so everybody is in an uproar. Three days before the first exam, Professor McGonagall announces that the Mandrakes are ready to be cut and used to restore the petrified victims. Everybody is delighted, and in the midst of the cheering, a very nervous looking Ginny Weasley seats herself near Harry and Ron. Harry asks her if she wants to tell them anything and Ginny nods, only to be interrupted by Percy, who takes her seat. Ron is outraged at this and declares to Percy that Ginny may have known important information about the Chamber of Secrets, and Percy blushes and says that what she was going to tell them was not about the Chamber, but about something she saw him doing. He refuses to carry the subject further.
Later that day, Lockhart is escorting his students through the corridors and complaining about the extra precautions taken, and Harry and Ron agree and kindly suggest that he leave them to escort themselves to the next class. Lockhart is pleased and leaves, and Harry and Ron dash toward Myrtle's bathroom, only to run into Professor McGonagall. They lie that they were going to visit Hermione, and miraculously she lets them go. Not wanting to get caught in their lie, the boys trudge to the infirmary and find, clasped in Hermione's hand, a piece of paper that, once wrenched out, displays a paragraph of information about the basilisk that fits right in with all of the eerie things that have happened: it lives for hundreds of years, speaks in Parseltongue and so could be the voice Harry hears, kills with its stare, is the enemy of spiders, and is killed by the crow of a rooster. Underneath this information, Hermione had written "pipes," and Harry and Ron realize that she meant the pipes in Myrtle's bathroom.
The boys dash to the staff room to show their findings to McGonagall, only to hear an announcement that another attack has occurred and teachers must report to the staff room immediately. Hiding behind a row of robes, Harry and Ron listen to the staff meeting and learn that Ginny Weasley had been taken into the Chamber of Secrets, and that written on the wall were the words, "Her skeleton will lie in the Chamber forever." McGonagall then announces that the school will be closed, the students sent home the following morning. At this point, Lockhart enters the meeting and all the teachers turn on him, challenging him to take on the monster by himself, since he is so boastful that he knows how. Lockhart titters nervously and leaves the room, and soon Harry and Ron walk to his office to help him by telling him what they know of the monster in the pipes, and they find him in his office packing his bags.
An exchange follows in which Lockhart confides that he has never fought a dark arts creature before in his life, but rather he has interviewed the people who did the things he claimed to do, and then erased their memory of the encounter before writing up their adventures as his own. He then prepares to erase Ron and Harry's memories, but Harry yells, "Expelliarmus!" as he learned how to so in the dueling club, and Lockhart's wand flies into Harry's hands. Together, he and Ron push Lockhart into Myrtle's bathroom, where they question her about her death, which was in fact caused by a pair of large, yellow eyes, and where Harry spies a small snake carved onto the taps on her sink. Speaking Parseltongue, Harry tells the tap to open and it does, revealing a large pipe into which Harry, Ron, and a reluctant Lockhart descend.
Inside the pipes, the three come upon a giant snakeskin. As they examine it, Lockhart snatches Ron's wand and tries to destroy the boys' memories, but Ron's wand backfires and destroys Lockhart's own memory, also causing an avalanche of rocks to fall, creating a solid barrier keeping Ron and Lockhart on the close- to-home side, and Harry on the other side. Harry calls to Ron to try to make a hole in the wall, while he himself trudges on alone through the tunnel. Finally he comes upon a wall engraved with glittering serpents. Harry instructs it to open, and he enters.
This chapter connects many of the uncertain and unresolved situations rising in their tension throughout the book. For one, Hermione has not failed to solve the mystery that has proved so elusive to Harry and Ron; she sought knowledge in the library and found it in the form of the basilisk description she has balled into her hand. Everything fits. All of the mysteries, voices and attacks suddenly make sense. Nobody has died yet because all of the petrified victims so far have seen the basilisk through something else; Mrs. Norris, a puddle of water; Colin, his camera; Justin, through Nearly-Headless Nick; Hermione and Penelope, through a mirror. Even while she is frozen like a rock, Hermione can still be of service, and through her research is the first part of the mystery brought into light. Ron and Harry's hunch about Myrtle proves also to be correct; the information she gives regarding her death is right in line with how a basilisk would most likely attack. The pieces of the puzzle have come together, revealing everything except for the Heir Slytherin himself. This having been ascertained, Harry and Ron can proceed into the chamber with a good idea of what to expect.
The truth about Lockhart also is revealed in this chapter, when he nervously edges out of the staff room when given free rein to tackle the monster. He confirms Ron and Harry's suspicions that he is a phony when he is packing to leave so as not to face the monster, and we know immediately that the defense against the dark arts post will be left open again (in the first book of the series, the defense against the dark arts teacher has to leave for being affiliated with Voldemort). Lockhart is utterly useless and actually detrimental to Harry and Ron as they venture into the tunnels to confront the basilisk, and luckily his role in the plot is made fair when he casts a memory- obliviating charm that backfires, leaving him blithering idiotically to himself. He gets what he deserves during this scene, and his punishment fits his crime.
Finally, Ginny has been unduly frightened by the attacks over the course of the year, and Percy has been upset about her terror and nightmares. In this chapter, we see that Ginny did in fact know something about the attacks, or else she, a pure-blood young witch, would not have been taken into the Chamber of Secrets. We also learn over breakfast that Percy has something he is hiding, suggesting that he is not the perfect prefect he wants everybody to believe he is. Perhaps she could have been saved had she been given the chance to confide in Ron and Harry, or perhaps not. At any rate, Percy is absolutely distraught by her disappearance, as could be expected. When Harry and Ron set down the tunnels to rescue Ginny and save their school, the revelations caused by all of these events shape their journey.