1. Moaning Myrtle's Diary: Harry finds a secret diary belonging to a deceased student named Tom Marvolo Riddle in Moaning Myrtle's bathroom. Through entries in the diary, Harry learns about the legendary Chamber of Secrets and Riddle's connection to it.
2. Parseltongue: Harry realizes he can speak Parseltongue, the language of snakes. This ability was bestowed upon him when Voldemort attempted to kill him as an infant.
3. Enters Chamber of Secrets: Harry, along with his friends Ron and Hermione, find the entrance to the Chamber of Secrets on the second floor of the girl's bathroom, guarded by a Basilisk, an enormous serpent that uses its gaze to kill or petrify its victims.
4. Mirror of Erised: Harry confronts Tom Riddle (who is revealed to be a young version of Lord Voldemort) in the Chamber of Secrets. Riddle tricks Harry into looking into the Mirror of Erised, a magical mirror that shows the viewer their deepest desire.
5. Reveals His True Form: At this moment, Fawkes, Dumbledore's phoenix, brings the Sorting Hat to Harry. Inside the hat, Harry finds the sword of Godric Gryffindor, the founder of Hogwarts, who was the only person known to have killed a Basilisk.
6. Phoenix Tears and Gryffindor's Sword: Fawkes' tears heal Harry's wounds caused by the Basilisk, and Harry uses Gryffindor's sword to pierce the creature's roof of its mouth, killing it.
7. Destroying the Diary: Back in Moaning Myrtle's bathroom, Harry realizes that Tom Riddle's diary is a Horcrux, a container that holds parts of Voldemort's soul. He destroys it by stabbing it with a Basilisk fang.
Through his encounters and trials, Harry successfully uncovers the creature's identity, locates the Chamber of Secrets, and effectively eliminates the threat posed by the legendary Basilisk, putting an end to the horrifying events that had been occurring at Hogwarts.