I have to hold my hands up here. I do not know that much about Harry Potter, I have not read it. But I have listened to the unabridged audiotapes while on a trip to London with my Grandparents. (I did spend a lot of time pointing out why
The Lord of the Rings was better

)
But I have many friends who have read all the books and have given me their opinion. From what they told me about it, that was the general view I got. So, I must apologise if I generalised too much. I was only going on what I had been told, which went along the lines of,
"Well," explained Friend, "he goes to this school and has a wonderful time and all that. Then this evil wizard chap-"
"All wizards are evil" says I,
"Yes, I know... Anyway, this chap comes along and everything goes wrong and he fights to return it back to normal... basically."
"Okay, I see."
So, there you go. My mistake.