The CIA is not the only secret organization hunting Jason Bourne. The Ministry of Magic wants him too and they've sent newly graduated Auror Harry Potter to collect him. Post DH and Ultimatum.
Vernon visits his accountant and has an unpleasant surprise. Fred and George find a new buisness opportunity. Dudley owes someone money. General mayhem ensues.
How did Petunia really find out about the Dementors?