It's Harry's third year at Hogwarts; not only does he have a new "Defense Against the Dark Arts" teacher, but there is also trouble brewing. Convicted murderer Sirius Black has escaped the Wizards' Prison and is coming after Harry.
A young wizard finds himself competing in a hazardous tournament between rival schools of magic, but he is distracted by recurring nightmares.
As Harry Potter begins his sixth year at Hogwarts, he discovers an old book marked as "the property of the Half-Blood Prince" and begins to learn more about Lord Voldemort's dark past.
With their warning about Lord Voldemort's return scoffed at, Harry and Dumbledore are targeted by the Wizard authorities as an authoritarian bureaucrat slowly seizes power at Hogwarts.
Harry ignores warnings not to return to Hogwarts, only to find the school plagued by a series of mysterious attacks and a strange voice haunting him.