Harry Potter is hanging out on a summers day - under his uncle's sitting room window. He's listening for news of recent murders, because [[BigBad Lord Voldemort]] is once again alive. Yet he's not hearing anything helpful. His friends have been in contact with him but don't seem to be telling him much about what's going on in the wizarding world. He's not sleeping well - when he's not having nightmares about the killing of Cedric, he's instead having disturbing dreams about corridors that end with locked doors.
He leaves and goes for a wander around the neighbourhood, but meets his piggish cousin Dudley. An exchange of insults ensues. Harry threatens Dudley with his wand, and Dementors show up. Dudley nearly loses his soul and is reduced to gibbering temporary insanity, while Harry is forced to fight them off with a Patronus charm. And who should arrive to rescue the duo but Mrs. Figg, the elderly neighbour who Harry used to stay with when the Dursleys went away.