Harry Potter and the Half-Blood Princeended with an intriguing cliffhanger, but the movies never fully delivered on this in the same way as the books. While Dumbledore’s death was the primary focus of this story’s ending, one particular mystery was left unsolved untilHarry Potter and the Deathly Hallows. In the books, this led Harry, Ron, and Hermione to discover some dark truths about Voldemort’s Horcruxes, as well as one of theHarry Potterseries' most ironic and tragic stories. Unfortunately, theHarry Pottermovies cut this woefully short.

Though Harry and Dumbledore risked everything to retrieve one of Voldemort’s Horcruxes at theend ofHarry Potter and the Half-Blood Prince, the locket they found turned out to be a fake. Harry only realized this after Dumbledore was killed, and it was a bitter truth to accept. It seemed to Harry that the headmaster had weakened himself for nothing since someone with the initials R.A.B. had switched out the Horcrux for a decoy necklace containing a letter to the Dark Lord.The mystery of who R.A.B.was and what he had done with the real locket was left forDeathly Hallows, but the movies dropped the ball.

Locket Horcrux Harry Potter - The Death Hallows

The Deathly Hallows Movie Didn’t Deliver On The R.A.B. Cliffhanger

The Big Mystery Of Half-Blood Prince’s Ending Got An Anticlimactic Resolution In The Movies

The letter Harry found in the fake locket inHarry Potter and the Half-Blood Princewas deeply intriguing, and it was immediately apparent that there was a story behind it. Going intoDeathly Hallows, the initials R.A.B. were Harry’s only clue about the location of a Horcrux—rather frustrating since Dumbledore hadn’t provided much additional information. Though the seventh movie saw Harry discover at No. 12 Grimmauld Place that R.A.B. was Regulus Arcturus Black, Sirius' brother, this was as far as the story ever went.

TheDeathly Hallowsmovieonly revealed that Regulus had stolen Slytherin’s locket and passed it on to Kreacher, who told Harry that Mundungus Fletcher had stolen it. This was, ultimately, the critical bits that Harry needed to know to lead him to Dolores Umbridge. However, the movie never delivered on the “how” and “why” Regulus did what he did. The character’s entire letter to Lord Voldemort was essentially ignored, andtheHalf-Blood Princemystery itself was made far less interesting. This was disappointing since Regulus' full story shined light on several other details within theHarry Potterseries.

Harry Potter - Michael Gambon as Albus Dumbledore in Horcrux Cave

The R.A.B. Story Was Among Harry Potter’s Most Ironic Twists

The Movies Missed Out On All The Meaningful Layers

In theHarry Potterbooks, Kreacher detailed the full story of how Regulus came to have Slytherin’s locket. Sirius' brother had been a Death Eater, and Voldemort requested the use of his house-elf, which Regulus obliged.The Dark Lord used Kreacher to test the Emerald Potionthat served as the primary protection over his Horcrux in the cave and left the poor elf to die. Luckily, Regulus grew worried about Kreacher and summoned him, ultimately making it possible for him to escape the cave and survive. The whole situation resulted in a change of heart on Regulus' part.

Regulus loved Kreacher, and the story the elf told him about the cave left him deeply disturbed and concerned about the Dark Lord. The young Death Eater returned to the cave with Kreacher and drank the Emerald potion himself so that Kreacher could take the Horcrux and destroy it. Regulus was killed in the cave, and a distraught Kreacher returned to No. 12 in despair. It’s a terribly tragic story, andthe details of this deliver on the mystery Regulus' note created inHalf-Blood Prince. Still, there are more covert layers here that add significantly to the Black family’s overarching tale.

Harry Potter Franchise Poster

Sirius heard that Regulus had tried to leave the Death Eaters, but he never learned the full truth.

Sirius Black despised Kreacher, and his hatred and mistreatment of the elf contributed to his undoing inHarry Potter and the Order of the Phoenix. Ironically, Sirius' own Dark-wizard brother had sacrificed his life to save this very same house-elf.Deathly Hallowsexplores the complex morality of characters like Dumbledore and Snape, andthis theme is perfectly reflected in Sirius and Regulus' ironic deaths. Unfortunately, theHarry Pottermovies missed this entirely.

Why Regulus Black’s Letter Was Important To Half-Blood Prince’s Story

Dumbledore Drank The Potion For (Almost) Nothing

Though the contrast inRegulus and Sirius' storiesis an intriguing feature within Kreacher’s tale inDeathly Hallows, this isn’t the only reason the R.A.B mystery was so important. Another layer within the irony is that, like Regulus, Dumbledore had allowed himself to be weakened by the Emerald Potion to protect the life of someone else. Voldemort considered house-elves and underage wizards useless and disposable, butRegulus and Dumbledore gave their lives to protect them. Of course, in both situations, this was, ironically, for nothing.

This poetic irony linked the final two books ofHarry Potter, and it’s unfortunate that such details are so often missed by movie adaptations.

Dumbledore’s death was all the more bitter at the end ofHalf-Blood Princebecause he and Harry hadn’t even been successful in claiming the Horcrux since Regulus had already gotten it. Regulus' death was also a waste since Kreacher had been unable to destroy the Horcrux until Harry retrieved it. Had Regulus never taken the locket, Harry and Dumbledore would have later, and the story would have come to the same end. This poetic irony linked the final two books ofHarry Potter, and it’s unfortunate that such details are so often missed by movie adaptations.