Emboldened by the return of Lord Voldemort, the Death Eaters are wreaking havoc in both the Muggle and wizarding worlds and Hogwarts is no longer the safe haven it once was. Dumbledore is intent upon preparing Harry for the final battle that he knows is fast approaching. He needs Harry to help him uncover a vital key to unlocking Voldemort's defenses -- critical information known only to Hogwarts' former Potions Professor, Horace Slughorn. Meanwhile, teenage hormones rage across the ramparts as Harry's long friendship with Ginny Weasley is growing into something deeper. But standing in the way is Ginny's boyfriend, Dean Thomas, not to mention her big brother Ron. Ron's got romantic entanglements of his own to worry about, with Lavender Brown lavishing her affections on him, leaving Hermione simmering with jealousy yet determined not to show her feelings. One student, however, remains aloof with far more important matters on his mind. He is determined to make his mark, albeit a dark one.