Harry Potter and the Half-Blood Prince

Harry Potter and the Half-Blood Prince is a fantasy novel written by British author J.K. Rowling and the sixth and penultimate novel in the Harry Potter series. Set during Harry Potter's sixth year at Hogwarts, the novel explores the past of the boy wizard's nemesis, Lord Voldemort, and Harry's preparations for the final battle against Voldemort alongside his headmaster and mentor Albus Dumbledore.

The book was published in the United Kingdom by Bloomsbury and in the United States by Scholastic on 16 July 2005, as well as in several other countries. It sold nine million copies in the first 24 hours after its release, a record that was eventually broken by its sequel, Harry Potter and the Deathly Hallows. There were many controversies before and after it was published, including the right to read copies delivered before the release date in Canada. Reception to the novel was generally positive, and it won several awards and honours, including the 2006 British Book of the Year award.

Reviewers noted that the book took on a darker tone than its predecessors, though it did contain some humour. Some considered the main themes to be love, death, trust, and redemption. The considerable character development of Harry and many other teenage characters also drew attention.

Plot

Severus Snape, a member of the Order of the Phoenix, meets with Narcissa Malfoy, Draco's mother, and her sister Bellatrix Lestrange, Lord Voldemort's supporter. Narcissa expresses concern that her son might not survive a mission given to him by Voldemort. Snape makes an Unbreakable Vow with Narcissa, swearing to assist Draco.

Dumbledore picks Harry up to escort him to the Burrow, home of Harry's best friend Ron Weasley. They detour to the home of Horace Slughorn, former Potions teacher at Hogwarts, and Harry unwittingly helps persuade Slughorn to return to teaching.

On the Hogwarts Express, Harry suspects Draco has become a Death Eater. Harry eavesdrops on Draco, who brags to his friends about a mission Voldemort has assigned him. Draco catches Harry, petrifying him and breaking his nose. Nymphadora Tonks finds Harry, fixes his nose and escorts him to Hogwarts, where Dumbledore announces that Snape will teach Defence Against the Dark Arts, while Slughorn will teach Potions. Finding an old textbook that once belonged to "The Half-Blood Prince", an individual who wrote numerous spells and tips in the book, Harry excels at the Potions class, winning a bottle of Felix Felicis, or "Liquid Luck". Hermione, however, distrusts the book.

Ron and Hermione grow closer, but after learning from his sister Ginny of Hermione's history with Viktor Krum, Ron goes out with Lavender Brown, making Hermione jealous. Harry develops feelings for Ginny, and the two later start a relationship with Ron's approval after a Gryffindor Quidditch victory. Draco grows unhinged throughout the year, acting in increasingly shady ways.

Meanwhile, to help Harry in his foretold battle with Voldemort, Dumbledore and Harry use the Pensieve to examine memories of people from Voldemort's past. One of the memories involves Slughorn conversing with a young Tom Riddle, but it has been tampered with, so Dumbledore asks Harry to obtain the real memory from Slughorn. Harry uses Felix Felicis to retrieve the memory, in which Slughorn tells Riddle about the process of splitting one's soul and hiding it in Horcruxes, making the user virtually immortal. Voldemort created six Horcruxes, which must be destroyed in order to destroy Voldemort himself. Two Horcruxes, Riddle's diary from Harry Potter and the Chamber of Secrets and a ring belonging to Voldemort's grandfather, have already been destroyed; four others remain.

Near the end of the year, Harry and Dumbledore journey to a cave to retrieve a Horcrux, Slytherin's locket. They find the locket in a potion-filled basin in the middle of a lake. To reach the locket, Dumbledore drinks the potion, severely weakening him. After fighting off Inferi hidden in the lake, Harry and Dumbledore take the locket and return to Hogwarts, and find the Dark Mark over a school tower. They ascend the tower and are ambushed by Draco, who reveals that his mission is to kill Dumbledore, and has helped Death Eaters get inside Hogwarts. However, Draco cannot go through with it. Snape arrives and kills Dumbledore instead. Harry ignores the battle raging in Hogwarts to pursue Snape, but is defeated by him. Snape reveals that he is the Half-Blood Prince before escaping.

After Dumbledore's funeral, Harry breaks up with Ginny, as their relationship puts her in danger. He discovers that the locket is a fake, containing a note from someone named "R. A. B.". Harry announces his intentions to search for Horcruxes the following year rather than return to Hogwarts. Ron and Hermione vow to join him.