Dumbledore's letter basically said that there will be an extra week or two of school this year. However, the students were only required to take one subject- muggle studies. This was because Dumbledore wanted to try out a "person teaches about their culture" thing like what they use to try to take out child brains in muggle school. Dumbledore brought this muggle in mainly just to show him that all of that could be done much easier. With just a single spell, you know?
As soon as Harry stopped reading that dreadful letter (uh-oh, I'm starting to sound just like Lemony Snicket, am I not? And my English teacher also.), Booklya put Harry in her claws, and lifted off into the night (can you guess which author I'm starting to sound like now?)
And so, Harry was taken to Hogwarts by owl blah, blah, blah, and was greeted at school by the MUGGLES OF DOOM. Then, strangely 1 by 1 the MUGGLES OF DOOM disappeared, except for one by the name of Tromedlov.
Harry just gasped.