
Now not only the wizarding world, but also the Muggle world is feeling the growing power of Voldemort, and Hogwarts is no longer a safe haven. Harry suspects that some danger lurks in the castle itself, but Dumbledore is more focused on preparing him for the final battle, which he knows is just around the corner. Together they try to unravel the secret of Voldemort's immortality, and to do so, Dumbledore invites his old friend and colleague, Professor Horace Slughorn, to be his potions teacher.