Times are darker than before.
Cornelius Fudge has been demoted from Minister of Magic. The ministry is sending out letters of ways to protect houses. Non-magic (muggles) and magic people are turning up dead. For two weeks Harry has to stay with the Dursleys. Dumbledore then escorts him first to meet Professor Slughorn then to the burrows. At the burrows Fleur De Lacour is engaged to Bill Weasley. Tonks is acting unusual, more sad.
When they go to Diagon Alley. Fred and George’s joke shop is booming as ever. Harry, Ron, and Hermione notice Draco alone walking into Knockturn Alley. They follow him to Borgin and Burks. Harry is wondering if Draco is now a death eater.
At the time during Hogwarts Dumbledore is showing memories to Harry. Memories containing bits of information about Voldemort. The most important memory Harry has to get from Professor Slughorn. Harry also has a potions book that was written in by someone named the Half-blood Prince. Harry excels in potions with this book which makes Hermione mad.
The end Harry loses yet another person close to him. Then he realizes that when he and Voldemort stand off he is the one that must finish Voldemort off.