Returning for his fifth year of study at Hogwarts, Harry is stunned to find that his warnings about the return of Lord Voldemort have been ignored. Left with no choice, Harry takes matters into his own hands, training a small group of students to defend themselves against the dark arts.

Harry, Ron and Hermione walk away from their last year at Hogwarts to find and destroy the remaining Horcruxes, putting an end to Voldemort's bid for immortality. But with Harry's beloved Dumbledore dead and Voldemort's unscrupulous Death Eaters on the loose, the world is more dangerous than ever.

As Lord Voldemort tightens his grip on both the Muggle and wizarding worlds, Hogwarts is no longer a safe haven. Harry suspects perils may even lie within the castle, but Dumbledore is more intent upon preparing him for the final battle fast approaching. Together they work to find the key to unlock Voldemorts defenses and to this end, Dumbledore recruits his old friend and colleague Horace Slughorn, whom he believes holds crucial information. Even as the decisive showdown looms, romance blossoms for Harry, Ron, Hermione and their classmates. Love is in the air, but danger lies ahead and Hogwarts may never be the same again.