Overview

Harry Potter and the Half-Blood Prince starts with an opening scene involving Bellatrix Lestrange and Narcissa Malfoy who are on their way to visit the home of Severus Snape. Narcissa wants to talk to Snape about a request that Lord Voldemort has made of her family, that her son Draco perform some sort of service though what the service is, exactly, we don’t know yet. Voldemort has forbidden her to speak of the plan to anybody and Bellatrix tries to persuade her not to go to Snape, but as it happens, Snape is already aware of the plan (much to Bellatrix’s anger as she does not trust Snape). Snape enters into the unbreakable vow with Narcissa and promises to watch over her son and attempt to help him as he carries out Voldemort’s orders.

Back at the home of the Dursleys, Harry has received a letter from Professor Dumbledore, stating that he will be coming to take him to the home of the Weasleys. While Harry is excited about this prospect, he finds it hard to believe that this is actually going to happen and neglects to prepare in advance, meaning that when Dumbledore shows up, he gets a less than warm welcome from the Dursleys. In the end, Dumbledore explains that Harry will need to come back to his aunt and uncle’s home one last time the following summer, in order to ensure the continuing protection of some complex magic that Dumbledore has invoked to protect him.

Before Dumbledore takes Harry to the Burrow (the Weasleys’ home), he and Harry go to see Horace Slughorn, a retired Hogwart’s teacher. Harry isn’t sure why Dumbledore wanted him to come along at first, and as Dumbledore chats with Slughorn and then leaves Harry alone with him for a few minutes, Harry becomes somewhat uncomfortable and a little put off as Slughorn talks about his long list of connections with former students who are now important or famous. As Harry and Dumbledore go to leave, Slughorn agrees to return to teach at Hogwart’s which he had been unwilling to do previously. We find out that this is in part because he would like to count Harry among his famous connections and also because of the safety offered by proximity to Dumbledore now that Voldemort is back in power.

Later, Harry visits Diagon Alley with the Weasleys and Hermione Granger and the three see Draco Malfoy who looks like he’s sneaking off somewhere. Harry, Ron and Hermione use Harry’s old invisibility cloak to follow Malfoy into Knockturn Alley where they see him bullying the owner of a shop that deals in Dark artifacts. Harry finds this extremely strange and going on what he sees in this scene in conjunction with a number of other strange occurrences, he begins to suspect that Malfoy has become a Death Eater. This prospect seems extremely unlikely to Ron and Hermione who believe Malfoy to be too young and inexperienced to be of any use to Voldemort.

Over the course of the year Harry is given secret lessons about Tom Riddle’s (Voldemort) past. Eventually, he is able to find out that Professor Slughorn, who had taught Riddle at Hogwart’s, had once given him some information on dark magic known as a horcrux. We learn that a dark wizard can split his soul by murdering and then conceal a piece in anything that he wishes to turn in to a horcrux — thus rendering him immortal (as long as the ripped piece of soul remains hidden). We also find out that Riddle/Voldemort had seemed inclined to attempt to rip his soul into seven pieces and create six horcruxes (the seventh piece of soul would continue to reside in his body).

Meanwhile, Harry has continued to suspect that Malfoy is up to something at Hogwart’s. He becomes more and more concerned about Malfoy’s activities but his thought on the matter are largely swept aside by his friends as well as Professor Dumbledore.

The book ends in disaster as Harry goes with Dumbledore to attempt to find one of Voldemort’s horcruxes, which Dumbledore believes he has managed to track down. After successfully entering the horcrux’s magically-protected hiding place and retrieving what they believe to be a horcrux, the two return to Hogsmeade near the school to find that the Dark Mark (Voldemort’s sign) has been set over the school. Harry and Dumbledoreimmediately fly to the tower where the Mark has been set. Hearing approaching footsteps, Dumbledore magically paralyzes Harry, who is under his invisibility cloak, but in that moment Malfoy appears and disarms Dumbledore. It becomes clear that Malfoy has been ordered to murder Dumbledore, but he appears to hesitate and eventually seems tempted to come over to the anti-Voldemort side as Dumbledore offers to give him and his family protection. At this point, death eaters, including Snape appear and Snape kills Dumbledore.

The book ends after Dumbledore’s funeral with Harry, Ron and Hermione making plans to search for the rest of Voldemort’s horcruxes.