Harry Potter and the Chamber of Secrets is the second novel in the Harry Potter series written by J. K. Rowling. The plot follows Harry's second year at Hogwarts School of Witchcraft and Wizardry, during which a series of messages on the walls on the school's corridors warn that the "Chamber of Secrets" has been opened and that the "heir of Slytherin" will kill all pupils who do not come from all-magical families (Mudblood).

These threats are followed by attacks which leave residents of the school "petrified" (frozen). Throughout the year, Harry and his friends Ron Weasley and Hermione Granger investigate the attacks, and Hermione herself is attacked by Basilisk (later found out that Basilisk lives inside the chamber).

In this series, Harry also discovers that he can speak Parseltongue, which is also an ability possessed by Salazar Slytherin, and everyone suspects Harry is the heir of the Slytherin. With his ability, he opens the chamber, and later finds Ginny, who actually has been talking to Tom Riddle through his diary and has been used by Tom Riddle to leave clues. Later Harry finds out that Tom is actually Voldemort. Inside the chamber, Tom orders Basilisk to attack Harry, and eventually Harry managed to kill Basilisk by using Griffindor sword brought by Dumbledore Phoenix (sword comes from the hat) and Harry destroys the diary using Basilisk's fang.