Harry struggles to uncover the identity of the Half-Blood Prince, the past owner of a potions textbook he now possesses that is filled with ingenious, potentially deadly, spells. But Harry's life is suddenly changed forever when someone close to him is heinously murdered right before his eyes.
As the Harry Potter sequence draws to a close, Harry's most dangerous adventure yet is just beginning . . . and it starts July 16, 2005.

We could tell you, but then we'd have to Obliviate your memory.