Banner by me! With the Horcruxes finally destroyed, Harry, Ron, and Hermione can finally let their families and friends know what has been going on, where they disappeared to, and what they have been doing. But it's too dangerous to send owls, so they start sending their letters to the mailbox at Order Headquarters, Number 12, Grimmauld Place. Unfortunately, due to some kind of mixup, the letters arrive at Number 11, where muggle Henry Fischer finds them along with his electric bill.
Henry comes home from work early with a bad cold. He finds something amiss in his mailbox. Then he pays the outrageously high electric bill and finds something ELSE amiss.