The war against Voldemort is not going well; even the Muggles have been affected. Dumbledore is absent from Hogwarts for long stretches of time, and the Order of the Phoenix has already suffered losses.
And yet . . . as with all wars, life goes on. Sixth-year students learn to Apparate. Teenagers flirt and fight and fall in love. Harry receives some extraordinary help in Potions from the mysterious Half-Blood Prince. And with Dumbledore's guidance, he seeks out the full, complex story of the boy who became Lord Voldemort - and thus finds what may be his only vulnerability.
For the rest of the book to go the "J.K. Rowling - 06 Harry Potter and the Half-Blood Prince" audiofolder.
Chapter 01 - The Other Minister
Chapter 02 - Spinner's End
Chapter 03 - Will and Won't
Chapter 04 - Horace Slughorn
Chapter 05 - An Excess of Phlegm
Chapter 06 - Draco's Detour
Chapter 07 - The Slug Club
Chapter 08 - Snape Victorious
Chapter 09 - The Half-Blood Prince