 While the Dursley <unk> uncle Vernon , aunt Petunia , and cousin <unk> a potential client for Vernon ’ s drill @-@ manufacturing company <unk> , Harry Potter reminisces upon the events of the previous year , including his enrollment in Hogwarts School of Witchcraft and Wizardry and confrontation with Lord Voldemort ( the Dark wizard whose reign seemingly ended when he killed Harry ’ s parents and attempted but failed to kill Harry himself ) , and laments the fact that the best friends he made at the institution have not written to him , even for his birthday , on which the novel opens . 
