Harry's punished because of the escaping snake through the rest of the school year. Even though it's summer, he's still tormented by Dudley and all of his friends from school. The bullies like to chase Harry and are always trying to hunt him down. Harry can't wait for the fall, when he'll start at a different school from Dudley. Dudley will be going to Mr. Dursley's old private school, while Harry's going to be attending the local public school.
Mrs. Dursley takes Dudley to buy his school uniform, and the Dursleys act super proud of Dudley; Harry thinks it's hilarious.
The next day, he sees Mrs. Dursley dyeing some of Dudley's old clothes gray for him to wear at school, and worries about how mock-able he'll look.
They're not paying much attention to him when the mail arrives.
For the first time ever, the mail includes something for Harry. The letter is on beautiful paper, addressed to him in his bedroom, and has a great wax seal.
He delivers the rest of the mail to the Dursleys, and is starting to open his letter, when Mr. Dursley snatches it from him and refuses to give it back. When he sees what's written there, he totally freaks out and shows it to his wife. Despite Harry asking for his letter, which belongs to him, the Dursleys won't give it back. He and Dudley squabble and get kicked out of the room.
They listen in and hear the Dursleys worrying that they're being spied on and deciding to ignore the letter. Mr. Dursley says he won't have it.
Later that day, Mr. Dursley tells Harry he's burned the letter, but thinks he should move into Dudley's second bedroom instead of sleeping under the stairs.
While Harry would usually have been so excited to get out of his cupboard, all he can think about is his missing letter.
The next day, Dudley can't believe that Harry's still in his second bedroom. He goes to get the mail and finds another letter for Harry. Harry and Mr. Dursley make a mad dash for the letter and they all tussle until Mr. Dursley grabs the letter. He sends Harry to his room. Although Harry's upset not to have this letter, he hopes whoever's sending them will keep doing so.
Harry gets up really early the next morning and sneaks downstairs. He wants to meet the postman and get the mail before everyone else does. As he moves to the door he steps on something that screams. He realizes his uncle got there first to keep him from getting the mail. Mr. Dursley tells him to go make tea. While he's gone, the mail arrives.
There are three letters addressed to Harry, and Mr. Dursley tears them all up, before nailing the mail slot shut.
The next day, twelve letters arrive for Harry; the day after that, 24 letters come.
The day after that, Sunday, Mr. Dursley is relieved because the mail isn't scheduled. But letters start flying into the house, coming through the chimney and fireplace. He freaks out and orders everyone to pack.
They all rush to the car and drive around aimlessly for a whole day, before stopping at some hotel outside a city.
The next morning, the hotel's owner tries to deliver a letter to Harry, but Mr. Dursley keeps him from getting it. They go on the move again, seemingly without a direction or destination. Harry realizes the next day will be his eleventh birthday.
Mr. Dursley directs them to an isolated shack, surrounded by water. It's cold and miserable, and a storm rages around outside. Mr. Dursley is sure they won't get any letters there.
The Dursleys divide the available blankets and beds amongst the three of them. Harry's left to sleep on the floor with only a small coverlet. He can't fall asleep and thinks about how his birthday is coming.
At midnight, as it turns into Harry's birthday, there's a tremendously loud knocking at the door.