Sirius Black escapes from Azkaban while Harry is at the Burrow over the summer. Sirius tries to sneak in there to talk to Harry.

In the summer before 3rd year, the Weasleys go on their vacation to Egypt sooner and return shortly before aunt Marge would visit. Harry is invited to the Burrow and the Dursleys let him go, because they don't want him around when Marge comes to visit. Sirius still sees the newspaper with the Weasley family picture in it, including transformed Pettigrew, and breaks out like in canon. Somehow, he finds out that Harry is at the Burrow, but instead of going after Pettigrew first, he tries to sneak inside so that he can talk to Harry.