Summary

Voldemort & his Death Eaters have come back to reclaim the power they once had. Professor Snape vows to protect Draco Malfoy, no matter the cost, by using the Unbreakable Vow spell. Dumbledore tells Harry Potter to come with him to help enlist Horace Slughorn to be a new teacher at Hogwarts. Harry then visits the Burrow along with his friends until school starts. Upon shopping in Diagon Alley, Harry discovers & believes that Draco is working for Voldemort as a Death Eater. Once at school, Harry finds a Potions textbook that once belonged to "The Half-Blood Prince", where spells & potion ingredients are self-written throughout the book. Dumbledore & Harry goes on trips into the memories of people who have a connection to how Voldemort came into power the first time.

In the pensieve, Harry learns about Voldemort's past & how he created seven Horcruxes in order to live forever. He discovers that Voldemort's diary & ring are already destroyed, leaving him five Horcruxes left to destroy. Upon winning a Quidditch match, Ronald Weasley finds himself a girlfriend named Lavender Brown & Hermione gets jealous of this. Later on, Harry realizes that he has feelings for Ginny Weasley. Harry eventually finds out that Draco is using the Room of Requirement to do Voldemort's bidding & he tries to find out what Draco is up to but fails. Awhile later, Dumbledore invites Harry to leave Hogwarts to find a Horcrux & destroy it.

Once the Horcrux is found, Dumbledore drinks the poison & Harry must fight the monsters that attack them. When they return to Hogwarts, Harry hides while Draco has his wand out towards Dumbledore. Professor Snape comes into view & murders Dumbledore. Harry gets angry that Professor Snape is a traitor & runs after him but he escapes. Harry looks closely at the Horcrux & it reads the name "R.A.B." The golden trio talk together pf plans on not returning to Hogwarts the following year & instead go look for the other Horcruxes to destroy Voldemort.

The Differences

⊱ In the book, Harry inherits Sirius' home, Grimmauld Place & Kreacher the elf. In the film, there is no mention of Sirius' will to Harry. It would have slowed the film down too much if they had this scene in the film.

⊱ In the book, Bill Weasley & Fleur Delacour live at the Burrow. Mrs. Weasley & Fleur have wedding conflicts. In the film, there is no mention of Bill & Fleur's wedding plans. I'm not sure why the director decided to keep this out of the film.

⊱ In the book, it mentions that Fenrir Greyback turned Professor Lupin into a werewolf. In the film though, there is no mention of this. My guess is that it wasn't necessary to have this scripted in the film.

⊱ In the book, Tonks discovers Harry on the Hogwarts train passed out. In the film however, Luna Lovegood comes to Harry's rescue on the Hogwarts train. No one knows why the director switched up the person who finds Harry.

⊱ In the book, it tells the story of Voldemort's descendants of the Gaunt family. However in the film, there is no mention of them. My guess is that the film would have been too long if they used this flashback of a storyline, so they did not use it.

⊱ In the book, the Burrow is not attacked by Death Eaters at Christmastime. In the film, the Burrow is attacked & the house sets on fire. My guess is that the director wanted this Christmas scene to have an intense moment for the characters.

⊱ In the book, it mentions that Voldemort asked to be a teacher at Hogwarts. In the film, it does not mention this anywhere. It would have been a cool memory flashback storyline to film though.

⊱ In the book, it tells us that Professor Snape is half wizard, half Muggle, & his mother's last name was Prince, hence the name Half-Blood Prince. In the film, we only see Professor Snape say that he is the Half-Blood Prince; no mention of why. I'm not quite sure why the director left this out of the film, as it would have explained the entire Half-Blood Prince name.

⊱ In the book, Harry hides the Half-Blood Prince's textbook in the Room of Requirement. In the film though, Harry is with Ginny & Ginny hides it instead. No one knows why the director switched up who tosses the textbook.

⊱ In the book, Ginny & Harry kiss at the last Quidditch match of the school year in front of the entire school. However in the film, they kiss in the Room of Requirement after Ginny tosses Harry's textbook. Having the Quidditch kissing scene in the film would have been a really good scene instead of them kissing in the Room of Requirement, but they did not include it.

⊱ In the book, Ginny & Harry dated throughout the book, but Harry broke it off to protect her from harm. In the film, there is no mention of this, just a bit of flirting. No one knows why the director did not put this into the film.