Two Horcruxes have been destroyed - Tom Riddle's diary, by Harry in the Chamber of Secrets four years earlier; and Marvolo Gaunt's ring, by Dumbledore during the summer before this school year.

Set during Harry Potter's sixth year at Hogwarts, the novel explores Lord Voldemort's past, and Harry's preparations for the final battle amidst emerging romantic relationships and the emotional confusions and conflict resolutions characteristic of mid-adolescence.

This results in Harry's immediate fame, and his being placed in the care of his muggle (non-magical) Aunt Petunia and Uncle Vernon Dursley.

Dumbledore asks Harry to retrieve a key memory from Slughorn regarding Slughorn's conversation with a sixteen-year-old Tom Riddle.

Harry uses some of his Felix Felicis to acquire the memory.

When the next school year begins, the Ministry of Magic appoints Dolores Umbridge as the new High Inquisitor of Hogwarts.

After forming an underground student group in opposition to Umbridge, Harry and several of his friends face off against Voldemort's Death Eaters, a group of Dark witches and wizards, and narrowly defeat them, though Sirius is slain in a rescue attempt.

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! When Harry was a baby, Lord Voldemort, the most powerful evil wizard in living memory, killed Harry's parents but mysteriously vanished after trying to kill Harry.

The book sold three million copies in the first 16 hours after its release, a record at the time which was eventually broken by its sequel, Throughout the five previous novels in the Harry Potter series, the main character, Harry Potter, has struggled with the difficulties that come with growing up and the added challenge of being a famous wizard.

Meanwhile, Ron is displeased with his younger sister Ginny dating anybody, forcing Harry to ignore his attraction.

After an argument with Ginny in which Ron's dating inexperience is made clear, Ron takes up with Lavender Brown, creating a divide between him and Hermione.

Harry then successfully apparates to Hogsmeade with Dumbledore.