of which have been destroyed: Tom Riddle's diary and Marvolo Gaunt's ring. They travel to a cave where Harry aids Dumbledore in drinking a potion that hides another Horcrux, Slytherin's locket. A weakened Dumbledore defends them from Inferi by creating a ring of fire, and apparates them back to Hogwarts, where Bellatrix, Greyback, and other Death Eaters have entered through the Vanishing Cabinet in the Room of Requirement that Draco has secretly connected to one in Knockturn Alley. As Harry hides, Draco appears and disarms the headmaster, revealing Voldemort chose him to kill Dumbledore. Draco hesitates; Snape, however, arrives and kills Dumbledore. As the Death Eaters escape, Snape reveals to Harry that he is the Half-Blood Prince. As Hogwarts students and staff mourn Dumbledore's death, Harry tells Ron and Hermione that the locket is fake and contains a message from "R.A.B.", who stole the real Horcrux intending to destroy it. Harry, Ron and Hermione agree to forgo their final Hogwarts year to hunt for the remaining Horcruxes. Cast Daniel Radcliffe as Harry Potter: A 16-year-old British wizard who now enters his sixth year at Hogwarts School of Witchcraft and Wizardry Rupert Grint as Ron Weasley: One of Harry's two best friends Emma Watson as Hermione Granger: One of Harry's two best friends Bonnie Wright as Ginny Weasley: Ron's sister and Harry's girlfriend Helena Bonham Carter as Bellatrix Lestrange: One of Voldemort's principal Death Eaters and Draco Malfoy's aunt Jim Broadbent as Horace Slughorn: The newly appointed Potions master who had held the position before Severus Snape Robbie Coltrane as Rubeus Hagrid: The Hogwarts gamekeeper and Care of Magical Creatures teacher at Hogwarts Warwick Davis as Filius Flitwick: The Charms master and head of Ravenclaw Tom Felton as Draco Malfoy: Harry's rival and recipient of Voldemort's secret mission Michael Gambon as Albus Dumbledore: The headmaster of Hogwarts Alan Rickman as Severus Snape: The former Potions master, current Defence Against the Dark Arts teacher and head of Slytherin Maggie Smith as Minerva McGonagall: The Hogwarts Transfiguration teacher, deputy headmistress and head of Gryffindor Timothy Spall as Peter Pettigrew: The Death Eater who betrayed Harry's parents to Voldemort; Pettigrew has no lines in this film, but appears as a servant at Snape's house David Thewlis as Remus Lupin: A member of the Order of the Phoenix and Harry's ex-Defence Against the Dark Arts teacher Julie Walters as Molly Weasley: The Weasley matriarch and