Harry arrives downstairs to see Aunt Petunia cutting a grapefruit into fourths. Oh, and Uncle Vernon reads the ''[[UsefulNotes/BritishNewspapers Daily Mail]]'', incidentally.
It's explained that Dudley has been put on a crash diet at the insistence of the Smeltings school nurse. While the Dursleys have, as always, dismissed Dudley's bad grades and the reports of bullying, there is no way around the fact that he's gotten so fat that there aren't Smeltings uniforms big enough for him anymore. Therefore, a grapefruit quarter is now everyone's entire breakfast. You see, Aunt Petunia has decided that they will all be following Dudley's strict diet, including ultra-skinny Harry. ''Especially'' including ultra-skinny Harry.
But Harry isn't just taking the Dursleys' crap anymore. He sent owls out to his friends and they responded by sending him food [[MyFriendsAndZoidberg as well as Hagrid's rock cakes]]. Harry has successfully concealed this food ([[RunningGag and possibly the rock cakes as well]]) in his room and the Dursleys remain oblivious to the fact that he isn't really following Dudley's diet.
The doorbell rings and Uncle Vernon gets it. A few moments later, he walks into the kitchen looking very angry and demands to see Harry in the living room. Uncle Vernon reads a letter from Mrs. Weasley, asking if Harry could see the Quidditch World Cup with them and spend the rest of the summer at their house. It turns out the postman rang the doorbell to ask about the envelope, which Mrs. Weasley had cluelessly covered completely with stamps, leaving only a tiny square to squeeze the Dursleys' address into. This breach of normality is SeriousBusiness to Uncle Vernon.
Harry asks if he can go and Uncle Vernon now faces a quandary. If he lets Harry go, it will get rid of him, but at the cost of making him happy. Harry pushes Uncle Vernon in the right direction by bringing up his supposedly murderous godfather and it works. When Harry gets up to his room, he discovers he has been brought a letter by the tiny owl Sirius gave Ron [[Recap/HarryPotterAndThePrisonerOfAzkabanC22OwlPostAgain at the end of the last book]]. Ron's letter explains that they will be picking Harry up regardless and that his parents just thought they should pretend to ask permission first. Curiously, Ron seems to have named the tiny owl "Pig", which puzzles Harry. The letter also mentions that Hermione will be joining them at the Burrow and that Percy has started working at the Ministry of Magic.
Harry sends a response to Ron with the little owl and his letter to Sirius with Hedwig. Once the owls are gone, Harry eats some of the birthday cake which his friends sent to him and happily contemplates how thoroughly he has pwned the Dursleys.