What’s it about?
Harry Potter and the Half-Blood Prince is the dark, complex sixth book in J.K. Rowling’s series. As Voldemort’s war engulfs both the wizarding and Muggle worlds, Harry returns to Hogwarts for a year filled with mystery, romance, and devastating loss. Guided by Dumbledore, Harry investigates Voldemort’s origins, searching for a way to defeat him once and for all.
Detailed Summary
The story begins as the wizarding and Muggle worlds reel from Death Eater attacks. The Ministry of Magic is in chaos, and even the Muggle Prime Minister is warned of the danger. Severus Snape makes an Unbreakable Vow to Narcissa Malfoy, swearing to protect Draco and help him with a deadly task assigned by Voldemort.
Dumbledore collects Harry from the Dursleys and together they visit Horace Slughorn, a retired Potions Master. Dumbledore persuades Slughorn to return to Hogwarts, hoping his connections and knowledge will be useful. At the Burrow, Harry reunites with the Weasleys and Hermione, and learns that Fleur Delacour is engaged to Bill Weasley, causing family drama.
At Hogwarts, security is tight and tension runs high. Harry excels in Potions thanks to an old textbook filled with notes from the mysterious "Half-Blood Prince," which gives him an edge in class but also exposes him to dangerous spells. Slughorn favors Harry, inviting him to exclusive “Slug Club” gatherings. Meanwhile, Ron and Hermione’s friendship is tested by jealousy, Quidditch drama, and romantic entanglements. Ginny and Harry’s feelings for each other deepen.
Draco Malfoy behaves suspiciously all year, vanishing from the Marauder’s Map and seeming stressed. Harry becomes obsessed with discovering Draco’s secret and believes Malfoy is now a Death Eater. Dumbledore begins giving Harry private lessons, using the Pensieve to share memories that reveal Voldemort’s past: his family history, his time at Hogwarts, and his transformation into the Dark Lord.
Through these lessons, Harry and Dumbledore discover that Voldemort split his soul into multiple pieces, creating Horcruxes—objects that anchor his life to the earth. To defeat Voldemort, all Horcruxes must be found and destroyed. Slughorn’s memory reveals that Voldemort made at least six Horcruxes.
Later, Harry uses the Prince’s spell Sectumsempra on Malfoy, seriously injuring him. Snape intervenes and punishes Harry, warning him about using spells he doesn’t understand. Meanwhile, Ron is poisoned but saved by Harry and Slughorn’s quick thinking. Tensions run high as Death Eater activity increases.
Near the end of the year, Dumbledore and Harry set out to retrieve a locket Horcrux from a secret cave. Dumbledore drinks a potion to access the locket, severely weakening him. Harry helps Dumbledore back to Hogwarts, where the Dark Mark is found over the Astronomy Tower.
On the tower, Draco arrives, revealing he has been tasked with killing Dumbledore, but cannot bring himself to do it. Death Eaters burst in, and Snape kills Dumbledore with the Avada Kedavra curse, fulfilling his Unbreakable Vow. Snape flees with Draco, revealing himself as the Half-Blood Prince.
In the aftermath, the locket is found to be a fake, containing a note from someone identified only as “R.A.B.” The wizarding world mourns Dumbledore’s death. Harry decides not to return to Hogwarts for his final year, vowing instead to find and destroy the remaining Horcruxes. Ron and Hermione pledge to stand with him, whatever dangers lie ahead.