Harry loses his temper when Aunt
Marge speaks disparagingly of his parents. He runs away from the Dursleys and
is picked up by the Knight Bus, an emergency transport for standed witches and
wizards. He learns that Sirius Black, a prisoner in Azkaban fortress, has escaped.
According to the conducter, Black murdered 13 people and was a supporter of
Voldemort. At Diagon Alley, Cornelius Fudge, the Minister of Magic, arranges
for Harry to stay at the Leaky Cauldron pub. Soon, his friends Hermione and
the Weasleys join him. Harry overhears Mr. and Mrs. Weasley say that Black wants
him dead. On the train to school, Harry and his friends sit with the new Defense
Against the Dark Arts teacher, Professor Lupin. The train suddenly stops,the
lights go out,and a dementor appears at the door. Harry hears screaming and
passes out. At Hogwarts, the students learn that dementors are guarding the
school from Black. In Hagrid's class, Malfoy is scratched by a hippogriff named
Buckbeak. In Lupin's class, the students learn to use a charm against a boggart.
Hermione's cat goes after Ron's rat causing friction between the two friends.
Harry feels left out when the other third-year students go to Hogsmeade.
The Fat Lady is slashed and vanishes from the portrait through which Gryffindor
students enter their tower. Everyone is on the alert for Black. In Qidditch
match against Hufflepuff, Harry sees the dementors and faints again. His
Nimbus
brookstick is destroyed. Lupin promises to help Harry fight the dementors.
The Weasley twins give Harry a map, which shows him how to get from Hogwarts
to
Hogsmeade. There, he joins Ron and Hermione for some shopping. At the Three
Broomstick, Harry learns that Black was his parents' friend and their Secret-Keeper,
but he betrayed them. He also learns of another friend, Peter Pettigrew.
At Christmas, Harry gets a Firebolt from an unknown giver. In a Quidditch
match against Ravenclaw, Harry uses his Patronus to get rid of some dementors
who
turn out to be Draco and his Pals. Ron wakes up yelling one night when Black
gets into the dorm. Hagrid has to take Buckbeak before a committee to defend
his behavior. Harry sneaks off to Hogsmeade again, but this time Draco sees
him. Snape catches Harry and takes away the map..
Read
the ending here... 
