When adapting books to movies, there are always going to be some things that get left out. This makes sense, as books are full of a lot of scenes and details that don’t always translate to film, and movies only have so much time to tell a story. Since the Harry Potter universe is rather rich and has a lot going on, there are many things in the movies that aren’t explained. This means that some of the things from the movies will be pretty confusing unless you’ve also read the books.
We’ve put together a list of these details from Harry Potter and the Prisoner of Azkaban that only make sense if you’ve read the books.
WHAT THE POINT OF THE FIREBOLT WAS
At the end of the movie version of Harry Potter and the Prisoner of Azkaban, Harry receives the Firebolt broomstick from Sirius. In fact, the very last shot is a freeze-frame of Harry’s face as he flies away. However, there doesn't seem to be much point to him getting this gift as the Quidditch season is over. In the book, Harry receives the gift much earlier in the year, but he doesn’t know who it’s from. This adds to the mystery of what is going on at Hogwarts and the suspense of Sirius Black, as Hermione assumes Black sent the broomstick as an attempt to hex Harry.
THE DANGERS OF TIME TRAVEL
In the book, it’s made very clear that time travel is quite dangerous. Hermione stresses the fact that it’s essential that their past selves don’t see them. If this happens, it could have severe consequences. However, in the movies, time travel seems more lighthearted. In fact, Hermione throws a rock at her past self to try to get them to move. This makes it so that the realities of time travel aren’t as explored as in-depth.
THE SIGNIFICANCE OF MOONY, WORMTAIL, PADFOOT, AND PRONGS
This is one of the biggest ways that the Prisoner of Azkaban movie drops the ball. While Harry does receive the Marauder’s Map from Fred and George, it’s never explained that it was Harry’s father and his friends who made the map. This is a key thing from the books, but in the movies, the significance of this map and of these characters is never talked about. The whole storyline about how the Marauders turned into Animagi and got into the Shrieking Shack is also left out.
THE HISTORY OF THE SHRIEKING SHACK
As mentioned briefly above, the Shrieking Shack isn't’ really explained in the movies. It’s assumed to be some sort of a haunted house. In the books, it’s made clear that the Shrieking Shack was never haunted. The noises people heard were actually from Lupin as he transformed into a werewolf. Without these details in the movies, it’s less clear what this building is or how it can be accessed. There are a lot of steps missing, so viewers just have to take things on faith.
CROOKSHANK’S POINT IN THE STORY
Crookshanks is another player in the plot of the book who doesn’t really feature in the movie. While in the film he’s mostly just there as a pet, he’s actually rather essential in the books. It’s Crookshanks who helps Sirius in his attempts to break into Hogwarts. He also tries to protect Sirius from Harry in the Shrieking Shack. While it might be hard to explain in a movie about how a cat could do this, not including these details does make Crookshanks nothing more than a pet.
THE RULES OF USING UNDERAGE MAGIC
In the movies, and even sometimes in the books, the rules of using underage magic are a bit confusing. There doesn't seem to be a lot of consistency in these rules and how they are applied. However, the movies really drop the ball in terms of consistency in Prisoner of Azkaban. We see Harry practicing the Lumos spell in his room at the start of the movie. Then, when he blows Aunt Marge up, he’s worried about getting in trouble for doing magic. This definitely doesn't make any sense, and it’s never really explained.
THE IMPORTANCE OF TRELAWNEY'S PROPHECY
In the book version, it’s made clear that the prophecy Trelawney tells Harry is one of only two accurate prophecies she’s ever made. While in the book, Trelawney makes this precision right before Peter Pettigrew's identity is revealed, the timeline is messier in the movie. It occurs earlier on a seemingly random day. This makes this prophecy feel disconnected and probably doesn’t resonate that much as important for people who haven’t read the book.
WHY EVERYONE THOUGHT SIRIUS KILLED THE POTTERS
The entire story of how Peter Pettigrew was the one who betrayed James and Lily Potter really isn’t explained that well. In the books, we learn that the Potters were protected by the Fidelius Charm and that Sirius was their Secret Keeper. It’s explained that they were convinced to change the Secret Keeper to Pettigrew. While all of the details might have been hard to explain in a movie, it did make it hard to understand why Sirius was thought to be the bad guy when it had actually been Pettigrew all along.
THE FACT BUCKBEAK SEEMS TO BE THE ONLY HIPPOGRIFF
In the books, it’s made clear that there are lots of hippogriffs in the world. When Hagrid introduces his Care of Magical Creatures class to them, there are many. However, in the movie, we only see Buckbeak. While this was likely to save money and time, it does make it seem a bit strange and leaves audiences asking if there are any other hippogriffs around.
In both the book and the movie, there are many instances where it seems like Sirius Black really is trying to kill Harry like everyone thinks. In the book, all of these situations are explained. For example, when Sirius breaks into Hogwarts, he does so to try to kill Pettigrew. In the movie, they don’t take near as much time to explain how all of the details connect and show that Sirius was innocent.