Harry Potter is a series of seven fantasy books written by J.K. Rowling, whose plot can be summed up as:
An Evil Overlord that was thought to be long gone is coming back. The Chosen One must defeat him by embarking on a epic quest to destroy magical objcets related to said Evil Overlord - objects that reveal ties between Our Hero and the antagonist. He has the assistance of a wise old Wizard with a long grey beard, that will leave him along the journey. Yes, you've seen it before
It's a much beloved young adult fantasy series that started as a story for kids and kinda grew in tone along with the age of the audience. Yes, you've seen that before, too
Would you like to know more?
The story is about an orphaned boy living with awful relatives who one day finds out he's a wizard and so goes to a Wizard boarding school where he makes friends, learns magic, does magical sports, learns about his family and gets wrapped up in affairs involving a Dark Wizard version of Hitler called Lord Voldemort and his associated assholes (including a Dark Wizard version of the Klan called Death Eaters and Nazgul rip-offs called Dementors). So basically the pipe dream of every disaffected teenager.
The books sold really well, got a series of very popular movies which grossed higher than any other series of movies in history, probably got a fair bit of people interested in fantasy literature (given that they were mainly targeted to young adult readers) and generated a moderate amount of skub back in its day before the haters moved onto things which were more uniformly panned. Given the target audience, it was also inevitable that the fandom created an unholy amount of fanfiction, including what's universally recognized as the worst fanfiction ever. But it is also the source of the best (and most batshit insane) fanfiction ever, as well.
In general the series has good characters, even though the main cast looks a bit lacklustre when you think about them, and the main antagonist has not much to him besides "I'm Hitler, but with magic".
The lore and world-building is at best hit and miss, and sometimes you feel that the author is pulling deus ex machinas and lore out of her ass to railroad the story forward, but the series is not the worst gateway drug to the world of fantasy literature a young kid could have, even if traditionalists would favor Tolkien.
Eh, no reason you can't try both.
- Harry Potter: The Boy Who Lived and main protagonist. An unassuming English kid with glasses that obtains a pet owl, and takes up his preordained destiny to enter a secret world of magic hidden in plain sight. The Dark Lord tried to kill him when he was a toddler, but his parents loved him and the spell bounced and made the Dark Lord vanish instead (if that raises questions you've probably already put more thought into it than the author did). Went to stay with his abusive aunt and uncle and didn't notice he was a Wizard until a hobo came to his house and told him. Not the smartest knife in the drawer, and for much of the series he's actually more hated than loved by the wizardry world due to him being an angsty kid and the author catering to the needs of his angsty kid audicence.
- Hermione Granger: Smart nerd girl and probably your first erection. When she gets a magical object that allows her to travel through time she uses it to study more instead of, for example, solving every problem ever. Out of the blue she decided to bone the Comic Relief character at the end of the last book despite treating him as a dimwit for 7 years.
- Ron Weasley: Redhead comic relief. That's about it. Once he had a pet rat that was an old hairy man in disguise and slept with him. His brothers, due to the Marauder's Map (a magical object that shows the location of everybody in Hogwarts, with all the unfortunate implications), probably knew about this and was totally ok with it.
- Voldemort: aka Magic Hitler. No, really. He wants to eliminate everyone with muggle ancestry, wizard or not. Why? Because his mother was raped after a love potion backfired. That sucks, but no need to take out your daddy issues on the rest of mankind. For half of the series he's in a ghostlike state until he gets himself a new, strangely noseless body, thanks to the fact that he split his soul up into a bunch of different objects. Is finally killed for real when Harry destroys all the Horucruxes - himself included. WHAT A TWIST! But then Harry's still alive because he's the master of the Deathly Hollows! DOUBLE TWEEST!