Harry Potter and the Prisoner of Azkaban

"'Welcome to the Knight Bus, emergency transport for the stranded witch or
wizard. Just stick out your wand hand, step on board and we can take you
anywhere you want to go.'"

When the Knight Bus crashes through the darkness and screeches to a halt in
front of him, it's the start of another far from ordinary year at Hogwarts for
Harry Potter. Sirius Black, escaped mass-murderer and follower of Lord
Voldemort, is on the run - and they say he is coming after Harry. In his first
ever Divination class, Professor Trelawney sees an omen of death in Harry's
tea leaves... But perhaps most terrifying of all are the Dementors patrolling
the school grounds, with their soul-sucking kiss...

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