Harry Potter and the Half-Blood Prince

Lord Voldemort is tightening his grip on both the wizarding and Muggle worlds, kidnapping wand-maker Garrick Ollivander from Diagon Alley and destroying the Millennium Bridge. The Malfoy family is disgraced when Lucius is apprehended and sent to Azkaban for his involvement with the Death Eaters. Voldemort instead chooses Draco to carry out a secret mission at Hogwarts. Draco's mother Narcissa and aunt Bellatrix Lestrange seek help from Severus Snape, who claims to have been acting as a mole within the Order of the Phoenix all along. Snape makes an Unbreakable Vow with Narcissa to protect Draco and fulfill the assignment if he fails.