"But won't they notice if you shut your ears in the oven door?"
-- Harry Potter
Dobby, a house-elf, arrives in Harry’s room to warn him not to return to Hogwarts, the Dursleys’ dinner party is ruined by Dobby’s antics, and Harry is locked securely in his room.
Calendar and Dates
The action of this chapter begins immediately after that of the previous chapter, then sketches in the next three days. Continuing with our wild assumptions about the day of the week in the previous chapter, where we guessed that since July 31 was a Tuesday in book one then logically July 31 would be a Wednesday the following year, we can now count days and state with completely unwarranted confidence that the rescue happened the evening of Sunday, August 4 or early in the morning of Monday, August 5.
Harry's 12th birthday
the Masons come to dinner
Uncle Vernon bars Harry's window
Late evening or early the next morning the Weasleys turn up to rescue Harry
Interesting facts and notes
The first cracks in the facade of the wizarding world begin to appear, as we learn of the existence and enslavement of house-elves, and the extremely poor treatment they often receive from humans.
"But why don't you leave? Escape?"
"A house-elf must be set free, sir. And the family will never set Dobby free..."
"Can't anyone help you? Can't I?"
Harry's question, together with the fact that Dobby doesn't suggest that there's anything Harry can do, suggests quite strongly that only a house-elf's proper master can set him or her free. Supposing for the sake of argument that Harry could have set Dobby free at this point - Dobby would have known that, and would have had to punish himself for being tempted to speak.
Dobby actually addresses this explicitly during his conversation with Harry in the hospital wing later on, in CS10. See that chapter for more on this subject.
The fact that Dobby can leave the premises of the Malfoy mansion - even if he has to punish himself when he returns - coupled with the fact that he can express his wish to be free, strongly suggests that Dobby has no legal redress with the Department of the Regulation and Control of Magical Creatures, or he could've tried that route already. Apparently there are no laws under which a house-elf can request that his masters be compelled to release him. (That is a deduction rather than a statement of fact in canon, but it appears to fit all the known facts.)
"Whatever you've heard about my greatness is a load of rubbish. I'm not even top of my year at Hogwarts; that's Hermione, she -"
But he stopped quickly, because thinking about Hermione was painful.
As was explained in the previous chapter, the long silence from Ron and Hermione - which is about to be explained by Dobby - has Harry wondering if, after all, they're really his friends, and even worrying a little if the whole thing hasn't been just some incredible dream. In a few moments Harry has exactly the same pained reaction to thoughts of Ron.
"Speak not the name!"
"Sorry," said Harry quickly. "I know lots of people don't like it. My friend Ron -"
He stopped again. Thinking about Ron was painful, too.
See remarks on Harry's reaction to thoughts of Hermione, above. Also note that Dobby is dropping yet another hint about the He-Who-Must-Not-Be-Named issue.
"Not - not He-Who-Must-Not-Be-Named, sir -"
Dobby explains why this remark wasn't quite a lie in the last chapter, "Dobby's Reward".
"You've just ruined the punch line of my Japanese golfer joke..."
Vernon Dursley tells racist jokes, apparently. Why am I not surprised?
"Have you been stopping my letters?"
How could Dobby do this? These letters would have been arriving over the past four weeks or so. Was Dobby gone from the Malfoy's home for a month? Or did he come and go between the Malfoy mansion and Privet Drive every day? Even if he was hanging around for a month, what sort of magic could he use to intercept post owls? That's not an easy thing to do. We are seeing a surprising and mysterious level of magical ability here. What else are house-elves capable of?
"...tell Petunia that very funny story about those American plumbers, Mr. Mason."
It sounds like Mr Mason isn't above telling an ethnic joke himself.
With a crack like a whip, Dobby vanished.
Disapparition seems to make this sort of loud noise. The sound of arrival is a faint pop. Incidentally, a house-elf's ability to Apparate is not completely identical to that of wizards. He can Apparate within Hogwarts, for example.
Dear Mr. Potter...
The tone of this letter is that of a form letter, in which the items to be filled in are [recipient's name], [magic that occurred], [time of incident]. The form is different from that received by Harry in OP2, but that can be explained due to the fact that that was for a second and more severe offence. If some kind of magical automated system is involved, it would be quite interesting to know how it operates.
This is our first exposure to specific wizarding laws, namely (Decree for the Restriction of Underage Sorcery, 1875, Paragraph C) and (section 13 of the International Confederation of Warlocks' Statute of Secrecy). This is also our second glimpse of the wizarding government, the first having been Hagrid's and Dumbledore's remarks on and contact with Fudge the previous year. It is interesting, and somewhat chilling, to note that the letter offers Harry no opportunity to defend himself against the charge - of which he is in fact completely innocent - but moves straight into delivering an official warning, without inquiry as to what happened or why.
It is of interest to note that little of Harry's magic, wandless or not, at number four has attracted the notice of the Improper Use of Magic Office as of the end of Half-Blood Prince. The only other occasions when such magic did attract attention were the Dementor attack before his fifth year (OP1, see below) and when Harry blew up Marjorie Dursley during the summer before his third year (PA2). For the Marge incident,Harry didn't get an owl, only a visit from the Accidental Magic Reversal Squad. It is possible, though by no means certain, that the only reason Harry received an owl on this occasion is that Dobby did something to ensure that the Improper Use of Magic Office would notice that magic had occurred.
See PA3 and OP1 for incidents where Harry used his wand near Privet Drive. Only for the latter incident - for which, of course, the Dementors were witnesses - did Harry receive an owl, and then only after a greater lapse of time than is shown here. Possibly the Dementors reported the incident to someone who then arranged for an owl to be sent, as opposed to any automated detection of underage magic having occurred.
The following morning, he paid a man to fit bars on Harry's window...
Three days later, the Dursleys were showing no sign of relenting...
So let's try to work out the date. The fateful dinner party was on Harry's birthday, July 31. "The following morning" would be August 1. Three days later would be August 4, and it was that night that the Weasleys turned up. We can't say for sure if the rescue happened before midnight, so technically the chapter ends either the evening of August 4 or early in the morning on August 5. However, if we believe the reference to the moon being up, the rescue would have had to have happened during the evening of the 4th, since the moon was already set by midnight.
He dreamed that he was on show in a zoo, with a card reading UNDERAGE WIZARD attached to his cage.
See the essay on Harry's dreams.
Exceptional character moments
Dobby's adoration of Harry appears to date from the moment that Harry first asked him to sit down, "like an equal".
Harry's reputation has definitely not gone to his head; Dobby's hero worship embarrasses him greatly, and Harry's first response is to try to make Dobby see Harry as he truly is (or at least as he sees himself). He also immediately and automatically acknowledges that Hermione, not he, is top of their year at Hogwarts; he respects her intelligence.
Although Harry is being severely underfed between being locked up on his birthday and the Weasleys' rescue, he saves about half his food for Hedwig.
Now that the Dursleys knew they weren't going to wake up as fruit bats, he had lost his only weapon.