Harry is spending a miserable summer vacation with the Dursleys, his only remaining family. While Harry's uncle and aunt was preparing for a dinner with a visitor, Harry was visited by Dobby. He was a house elf. Dobby told Harry not to return to the Hogwarts, Harry's school in the previous years. It is a magical school for witches and wizards. Because Harry doesn't agree on what Dobby said, Dobby ruin the dinner that causes Mr. Dursleys to imprison Harry in the rest of the summer vacation. Fortunately, Harry's friends including Ron Weasley help Harry to go back to the Hogwarts.

By doing some research, Harry, hermoine and Ron discovered that a chamber opened at Hogwarts fifty years ago and a student was killed.

In order to catch the culprit, Hermoine, Harry and Ron make a Polyjuice. It is a potion that allows them to copy the bodies and face of Slytherins and to ask Malfoy abou the Chamber of Secrets. They find out that Malfoy is not the heir of the Slytherin. Right before the Valentines Day, Harry finds a diary in a broken toilet which belongs to Moaning Myrtle who haunts in the girls comfort room. Everytime, Harry asks a question through writing it responds back to Harry through writing also. It show Harry who Tom Riddle is.

Hermoine and a Ravenclaw girl are mysteriously pertrified. Harry and Ron go out of the caste to ask Hagrid. But before they reach Hagrid, the Minister of Magic, Cornelius Fudge and Lucious Malfoy remove Hagrid and Dumbledore from Hogwarts. As Hagrid led away, he instructs the boys to following the spiders,  to find out about the Chamber monster. Several nights passed, Ron and Harry sneak out the Hogwarts to do what Hagrid say. They found out that the monster who killed the girl several years before was not a spider and Hagrid is innocent. Ron and Harry was almost killed by a colony of giant spiders. They discover that Moaning Myrtle must be that girl killed by the monster.

Because of some clues they noticed from Hermoine, they find out that the monster is a basilisk. Ron help Harry to enter the Chamber.Tom Riddle unexpectedly turn into a younger version of Voldemort. Harry asks help from Dumbledore. Several moments pass, A phoenix and a magic hat which sent by Dumbledore arrived.Through the Magic hat and the phoenix's help, harry defeated the Basilisk and Tom Riddle. After that, All is well in the castle as the students leave for their summer vacations.

References:




http://www.sparknotes.com/lit/potter2/summary.html