The next morning, Harry is trying to persuade Hedwig to get in her cage when Ron comes in, annoyed about Percy. Harry tries to tell Ron about what he learned but Fred and George interrupt. Finally, everyone assembles downstairs with their trunks and animals. Hermione assures Crookshanks that she'll let him out on the train, while Ron snaps that Scabbers needs his peace. Mr. Weasley motions for everyone to follow him outside and into two cars. They reach the station early and then go through the barrier between platforms nine and ten in pairs.
Ron's snappiness suggests that he's already concerned that it's going to be a tough year for Scabbers, but notice that he's taking it out on Hermione, not on Crookshanks himself. This suggests that he's placing an unfair amount of blame on Hermione, something that makes his youth and immaturity clear and foreshadows their fights throughout the year.
Upon getting through the barrier Percy immediately goes to find Penelope Clearwater, his girlfriend. Ginny and Harry laugh at him and once everyone else is on the platform, they find an empty carriage. Mrs. Weasley kisses Harry goodbye and then Mr. Weasley calls Harry to come talk with him. Before Mr. Weasley can say anything, Harry says that he already knows about Sirius Black and isn't afraid. Mr. Weasley leads Harry back to the train and then asks for Harry's word that he won't go looking for Black. Harry is confused as he steps onto the train. As soon as the platform is out of view, he tells Ron and Hermione that they need to speak in private.
Mr. Weasley's request that Harry won't go looking for Black makes it very clear that there's more to the story that he's not telling Harry. Harry's confusion suggests that he's aware of this on some level, but notice that he doesn't question why Mr. Weasley would ask this of him. This again shows that Harry is young still and doesn't have well-developed critical thinking skills yet.
Harry, Ron, and Hermione find a compartment that's empty save for a man asleep. He looks ill and exhausted. Hermione reads his case, which reads that he's Professor Lupin—presumably, the new Defense Against the Dark Arts teacher. Harry shares what he overheard and what Mr. Weasley just made him promise. Hermione is horrified, while Ron insists that Harry would have to be stupid to go looking for Black. As they worry, Ron hears a tinny whistle. He pulls out Harry's Pocket Sneakoscope, explains where he got it to Hermione, and then stuffs it into a pair of socks and back into Harry's trunk.
Again, Ron's assertion that Harry would be stupid to look for Sirius Black shows that he too doesn't have fully developed critical thinking skills yet, as he fails to ask why Harry would want to do this in the first place and fails to recognize that the promise betrays that there is a reason, whatever it may be.
Ron says that the Sneakoscope might be faulty and suggests that Harry get it checked in Hogsmeade. Hermione is very interested in Hogsmeade; it's the only non-muggle village in Britain. As she spouts off facts, Ron talks about all the candies he's going to buy at Honeydukes, the sweetshop. When they finally turn to Harry, Harry glumly explains that he can't go since the Dursleys didn't sign his permission form. Ron says that if McGonagall won't sign it, Fred and George probably know a secret passage to sneak Harry out. He also says that Black wouldn't dare attack Harry if he and Hermione were around. Hermione scoffs.
Here, Ron's insistence that the Sneakoscope is faulty shows that he's unwilling to think critically about the people around him right now. As the trio learns later, the Sneakoscope is going off because Scabbers is actually the wizard Peter Pettigrew. While there's no reason at this point for Ron to suspect this, the fact that he blames the Sneakoscope and not Crookshanks, who would be a convenient scapegoat, indicates that Ron is indeed beginning to grow and mature.
Hermione lets Crookshanks out of his basket. The cat immediately jumps onto Ron's lap and Hermione raises her voice when Ron shoves Crookshanks away. They go silent when Professor Lupin stirs, but he stays asleep. Crookshanks finally settles in an empty seat and watches Ron intently. An hour later, Draco Malfoy and his cronies, Crabbe and Goyle, stop by the compartment to ridicule Ron, but they leave when they notice the sleeping professor.
The fact that Malfoy, Crabbe, and Goyle stop bullying Harry and Ron when they see a professor adds another facet to the idea of perspective, as it suggests that these bullies understand that who's around to witness their bullying matters.
The weather grows increasingly worse and by evening, it's dark and pouring outside. Ron is thrilled when the train starts to slow down but Hermione insists it's too early to be there. The train comes to a stop and without warning, the lights go out. Ron sees people coming onto the train as Neville lets himself into the compartment, trips over Harry, and sits down. Hermione tries to leave, but runs into Ginny on her way out. As they argue, they hear Lupin tell them to be quiet. Lupin conjures a handful of flames, tells the students to stay put, and then moves towards the door.
In the dark when nobody can see what's going on, it becomes clear that the students are young and can't necessarily fix things for themselves—they need an adult like Lupin to step in, take charge, and keep them safe. This reinforces the novel's assertion that Harry and his friends are at school to learn from teachers like Lupin, who ideally have their students' best interests at heart.
Before Lupin reaches the door, a towering, cloaked figure opens it. Harry sees that it has a slimy and scabby hand. The creature starts to draw a rattling breath and a feeling of cold sweeps over everyone in the compartment. Harry's eyes roll back, he hears a rushing in his ears, and then he hears a terrible scream. Suddenly, Harry wakes up to Ron slapping his face. The lights are on and the train is moving, but Harry feels ill. After he retakes his seat, he asks who screamed. According to Ron, nobody did. Lupin begins to break up a bar of chocolate and distributes the pieces. He explains that that was a dementor and goes to talk to the conductor.
Harry and the reader soon learn that chocolate is an antidote to the dementors; this then becomes an early indicator that Professor Lupin knows what he's doing when it comes to the Dark Arts. This helps the students come to think of him already as a protective and trustworthy figure, while it also offers hope that his lessons will be more useful than what Harry and his classmates have learned in years past from questionably qualified professors.
Harry asks what happened, and Ron explains that Harry started having a fit. Professor Lupin approached the dementor and when it didn't move, he shot something silvery out of his wand at it. Nobody else fell out of their seats, however. Lupin returns and encourages everyone to eat the chocolate, and Harry feels warmth spread to his fingers as he does. The compartment is silent for the rest of the journey.
By having Ron describe what the reader later learns is a Patronus as "something silvery," it shows how, without the knowledge of what the Patronus was, Ron can't properly describe what he saw. This makes the case that people must always be on the lookout for knowledge.
At the Hogsmeade train station, Harry, Ron, and Hermione hear Hagrid calling for the first-years. They follow the older students to coaches drawn by invisible horses and begin the ride to the castle. Harry notices two dementors on either side of the gate. To make things worse, when he gets out of the carriage, Malfoy maliciously asks if Harry actually fainted. He stops, however, when Lupin asks if there's a problem.
Again, Malfoy's unwillingness to taunt Harry in front of a teacher shows that he does respect the authority of teachers and knows they can get him in trouble. However, with this knowledge, Malfoy can simply get sneakier about how and where he taunts Harry.
Harry, Ron, and Hermione enter the castle but before they can go into the Great Hall for the feast, they hear Professor McGonagall calling for Harry and Hermione. Ron goes to the feast alone as Harry and Hermione follow McGonagall to her office. Madam Pomfrey, the nurse, joins them at the office and immediately begins fussing over Harry. Madam Pomfrey says that he at least needs chocolate and is thrilled when she hears that Lupin already gave Harry some. With this, McGonagall excuses Harry. He waits a few minutes until Hermione and McGonagall are finished and then they head for the Great Hall.
Notice that Harry never questions what McGonagall needed to talk to Hermione about. This shows a major lack of curiosity that will, throughout the novel, keep Harry from understanding what Hermione is doing much of the time. With this, the novel makes the case that Harry will need to develop his sense of curiosity and his critical thinking skills if he wants to be able to see and understand things fully.
As Harry and Hermione walk towards the Gryffindor table, Harry notices that people are pointing at him. Before he can tell Ron what McGonagall wanted, Professor Dumbledore stands to address the school. He explains that the dementors of Azkaban are at the school and that nobody may leave without permission. He says that dementors won't fall for tricks, disguises, or Invisibility Cloaks, and that they don't understand pleading or excuses. Then, Dumbledore introduces Professor Lupin. Ron notices that as the school applauds for Lupin, Professor Snape looks at Lupin with loathing. Dumbledore also announces that Hagrid will take over for the recently retired Care of Magical Creatures professor.
The way that Dumbledore describes the dementors suggests that they're not especially interested in justice, given that Dumbledore implies that errant students are at risk just as much as the criminal Sirius Black is. Remember that the dementors are an arm of the government as much as anything else—this starts to show that maybe Harry shouldn't think of the Ministry of Magic as trustworthy and, instead, should treat them more like he's being told to treat the Dementors.
With this, the tables fill with food. After the feast is over, Harry, Ron, and Hermione congratulate Hagrid, who seems overcome with emotion. The Gryffindors all climb up to Gryffindor tower and, at the portrait of the Fat Lady, Percy tells them that the new password is "Fortuna Major." As Harry climbs the stairs to his dormitory, he feels that he is home at last.
Now that Hagrid has been made a professor, he has even more responsibility to guide his students and make sure that they come away with a solid understanding of how to deal with magical creatures. His emotion at this suggests he understands the gravity of his promotion.