also: Plot of Part 1 As Lord Voldemort retrieves the Elder Wand from Albus Dumbledore 's grave, Severus Snape has become Hogwarts headmaster. After burying Dobby , Harry Potter has the goblin Griphook help him, Ron , and Hermione break into Bellatrix Lestrange 's vault at Gringotts bank, suspecting a Horcrux