A/N: This story is decidedly AU after the Half-Blood Prince, but I've been planning it for so long that I'm going to go ahead and write it anyway. Let's just say that if the characters belonged to me and not to J.K. Rowling, something like this would definitely have been included in that book! ;)
If things kept going at this rate, this was definitely going to be Dudley's best vacation from Smeltings ever! Things had started out rather badly. After he'd been home only a few days, Dudley and his mother had been escorted to Hogwarts, where the term was still wrapping up, by the formidable wizard Dumbledore. At first he'd been terrified, but by the end of his very eventful day there, he'd had an adventure (one that was scary at the time but kind of neat now that he looked back on it) and made a new friend. A new friend who just happened to be a wizard, and whom he'd invited rather impulsively to spend the summer at his house.
After a lot of discussion and a significant bribe (with this thought, Dudley glanced at his new PS2 with a look of smug satisfaction), Mumsy had gotten him to understand that the whole summer was a very long time to spend with someone he'd just met, and that anyway, Draco's mother was unlikely to let him leave home for quite that long. After all, summer was the only time in the whole year she got to see her son, and if Mrs. Malfoy was as devoted to her little boy as Mummy was to her own precious Dudders (here she'd stroked his cheek and looked at him with that gleam in her eye that only he could give her), she'd never be willing to let him go for the entire summer. After some more negotiation (and at this, Dudley's glance fell upon the new boxing gloves hanging in the closet), it had been decided that Draco would be invited to stay one week.
Since they didn't know Draco's postal address, Dudley had been forced to be civil to his cousin Harry just long enough to borrow his owl. He'd written a short note to Draco inviting him to come visit any week during the summer that he'd like, and to send a reply stating when that would be. Mumsy had written a longer letter to Mrs. Malfoy full of details about their charming home in Little Whinging and Vernon's responsible position in the community and how pleased they would be to welcome Draco into their thoroughly respectable lifestyle for a week. The owl had been sent off, and only two days later it had returned, bearing an enthusiastic letter from Draco saying he'd be there the next Monday, and a short, curt letter from Mrs. Malfoy thanking Mrs. Dursley for her hospitality.
The only problem in all this was that Daddy didn't know anything about it. Dudley wasn't used to keep secrets from his father, but Mummy had convinced him with a summer's worth of karate lessons that it would be best if Daddy didn't know anything about Draco's visit right now, and that right before Draco came they'd just say that he was a friend that Dudley had met at school, and there was no need for him ever to know that the school was Hogwarts or that Draco was a wizard.
Although he'd never have admitted it to her and risk not getting his bribe, Dudley had to admit that his mother had a point. Vernon Dursley, ordinarily such a good and generous daddy, could be kind of scary when faced with any kind of evidence about the wizarding world. When they were little, Dudley had blamed this all on Harry. If that little twerp hadn't been able to do all those magical things, then his daddy would never have had a reason to get mad. But now that he'd actually been to Hogwarts and seen it for himself, he knew that there were a lot of things in this world besides Harry that would make his father red in the face and sputtering. And unfortunately, his new friend happened to be one of those things.