1 As Lord Voldemort retrieves the Elder Wand from Albus Dumbledore 's tomb, Severus Snape has become Hogwarts ' headmaster. Meanwhile, after burying Dobby , Harry Potter speaks with the goblin Griphook about breaking into Bellatrix Lestrange 's vault at Gringotts bank, suspecting that a Horcrux may be hidden there. Griphook agrees