dxp4acu said:
Anyway, what should I know? Can someone fill me in? Anything important before this one?
OK - I'll have a go...
Background. Harry's wizarding parents were killed by Lord Voldemort (You Know Who) who was a wizard specialising the the Dark Arts but he (Harry) survived a death curse thanks to the strength of his mother's love. He's the only person to survive that curse which gave him his distinctive scar. The wizarding world all know about Harry Potter; the Muggle (our) world don't.
Book 1 - Harry learns the above and goes to Hogwarts school of witchcraft and wizardry. He becomes good friends with Ron and Hermione (in his Gryffindor house) and doesn't like Draco Malfoy (who's father was involved with Voldemort and is in Slytherin House). We learn Voldemort isn't quite dead yet although he doesn't have a body. But he has managed to convince a weak-minded wizard, who happens to be Harry's Defence Against the Dark Arts teacher, to allow him to share his body. This teacher is trying to steal the Philosopher's Stone (which Dumbledore - the wizard Voldemort fears most - has hidden at Hogwarts); the store will help restore Voldemort to a more physical presence when he will have more power.
Harry, Ron and Hermione figure out that someone is trying to steal the stone and follow. They think it's Snape though who is their 'evil' Potions teacher and head of Slytherin. But they get the stone and Voldemore flees when Dumbledore returns.
Book 2 - The Chamber of Secrets.
Students at Hogwarts are being found 'frozen' around the school by the stare of a basilisk. This has happened once before and eventually a student died. There are threats the school will be closed down.
It turns out that Voldemort is once again behind it as he tries to get a 'body' to use. Ron's little sister found a diary where she could have a 'conversation' with the old owner. She didn't know that the old owner was Voldemort as a boy. He instructs her to let the basilisk escape and eventually takes her to its chamber where he possesses enough of her soul to almost be able to take over her body. Harry rescues her from there and kills the basilisk and the 'diary'
Book 3 - The Prisoner of Azkaban
A prisoner has escaped from Azkaban, the wizard prison, and the Dementors (guards who suck the happiness out of people) are stationed around Hogwarts. The escapee is Sirius Black, the person who was convicted of helping Voldemort murder the Potters and killing many others; he's also Harry's godfather since he was the Potters best friend. The Dementors badly affect Harry since they bring back memories of his parents' deaths.
At the end, Harry, Ron and Hermione end up in a ramshackle hut with Sirius Black, who is an Animagus who can turn himself into a large dog - and their Dark Arts teacher, Lupus who is a werewolf (both Sirius and Lupus were Harry's dad's friends). Sirius explains that he wasn't involved in killing the Potters; instead it was the fourth member of the friends; Wormtail but he's been missing, assumed murdered by Sirius for the last 14 years). He was jealous of the success of the others and turned to Voldemort.
Sirius realised he was still alive when he saw a picture of Ron and his family. Ron has a pet rat (the animal the Wormtail could become) who is in fact Wormtail. They turn him back into a human and he confesses but while they are escapting, the full moon appears, Lupus becomes a werewolf and Wormtail escapes. Sirius is recaptured and the Dementors are scheduled to come to 'zombify' him. But Dumbledore believes Harry and his pals; and lets them use Hermione's timetwister device to go back in time and rescue Sirius from his cell before the Dementors arrive. Wormtail has still escaped though and the fear is that he will try to find Voldemort and help him.
EDIT - eesh... that turned out horrifically long! Sorry!