The next morning, Harry, Hermione, and the Weasleys leave to catch the train to Hogwarts. However, before Harry boards the train, Mr. Weasley pulls Harry aside. Harry confesses that he heard the Weasleys talking last night, so he knows that Sirius Black is after him. Mr. Weasley asks Harry to promise not to go looking for Black, but Harry doesn’t understand why Mr. Weasley thinks Harry would look for someone who wants to kill him. On the train, Harry, Ron, and Hermione find a compartment with only one person inside: a shabby-looking man who is fast asleep. They read the name on his luggage and discover that he is Professor Lupin. Harry’s Sneakoscope starts to whistle, but thinking it’s just faulty Harry stuffs it into a pair of socks to silence it. Suddenly, the train stops, and their compartment door opens. A hooded figure with “glistening, grayish, slimy-looking, and scabbed” hands enters, “trying to suck something more than air from its surroundings” (83). Harry hears someone screaming, and he faints. When he awakens, Professor Lupin, Ron, and Hermione explain that the creature was a dementor: one of the guards of Azkaban looking for Sirius Black. Lupin managed to drive it away with a spell.