The Harry Potter novels take place in Hogwarts School of Witchcraft and Wizardry, a castle in the middle of a ring of mountains, usually accessed from platform 9 3/4 at King's Cross train station, London. It is in Scotland, according to a margin note in "Fantastic Beasts".
Each book in the series chronicles one year in Harry's life at Hogwarts. There are supposed to be seven books, each getting a little bit darker than the previous one as Harry gets older.
Harry Potter and the Philosopher's Stone
After his parents are killed by the evil Lord Voldemort, 15-month old Harry Potter is sent to live with his abusive Aunt Petunia and Uncle Vernon. They force him to live in a cupboard under the stairs, while they spoil their son Dudley with constant toys and treats. The week of his 11th birthday, Harry starts getting letters, delivered by owls, inviting him to come and study at a Hogwarts School of Witchcraft & Wizardry. After an intervention by the gigantic Hagrid, Hogwarts' groundskeeper, he is finally permitted to attend, although his aunt and uncle tell everyone that he is attending St. Brutus' School for Incurably Criminal Boys.
At Hogwarts, he befriends Ron Weasley, the youngest son of a poor wizarding family, and Hermione Granger, a Muggle-born girl (not of a wizarding family) who is the smartest witch of her age, and develops a rivalry with brat-prince Draco Malfoy.
The main plot revolves around the contents of a forbidden room, which Harry and friends eventually discover contains the philosopher's stone. Using it, Lord Voldemort will be able to resurrect himself from his mysterious death while attacking the infant Harry. It remains for the three protagonists to prevent this.