The Minister of Magic visits the Muggle Prime Minister to inform him that Voldemort is back and wreaking havoc on the wizarding world and the Muggle world.
Meanwhile, Bellatrix and Narcissa visit Snape, imploring the professor to help Draco. Voldemort has given Draco an assignment and Narcissa is worried. Snape makes an Unbreakable Vow to watch over Draco and carry out Voldemort’s orders if Draco fails.
At the Weasleys, Harry arrives and learns that Bill and Fleur Delacour are engaged. Harry, Hermione, and Ron receive their O.W.L. (Ordinary Wizarding Levels) test scores. Harry failed Divination and History of Magic, but did well in everything else.
Harry receives news that he is the new Quidditch Captain. The friends head to Diagon Alley, which is more empty than usual because people are afraid. They go to Fred and George’s joke shop, which is thriving despite the depression in Diagon Alley. Harry spots Draco Malfoy outside, and follows Draco to Borgin and Burkes, a store that sells Dark Arts objects. Draco asks the proprietor to keep something for him and repair it.
Afterward, Harry sneaks into Slytherin’s train compartment to spy on Draco, and hears Draco bragging about moving on to better things. As everyone disembarks, Draco catches Harry, paralyzing him with magic, breaks Harry’s nose, and throws the invisibility cloak over him and leaves him there.
Luckily, Tonks discovers and frees him. She is stationed near the school as security. At the gate, Snape walks him back to the school, berating him for his tardiness.
Dumbledore announces a new Potions teacher, Horace Slughorn. To everyone’s shock, Snape has been appointed the Defense Against the Dark Arts teacher.
In Potions, Slughorn has them mix up a “Draught of the Living Death.” Harry makes the best potion by following handwritten directions in his textbook, and wins a luck potion. He finds “This book is property of the Half-Blood Prince” written in the book.
Harry starts private lessons with Dumbledore. At his first lesson, they use the Pensieve to visit memories that will help Harry survive. They witness Voldemort’s mother, Merope, who was part of a violent, unstable wizarding family, the Gaunts. Merope uses a love potion to marry Tom Riddle, Sr., later bearing his child. However, Tom leaves her and the child when the potion wears off.
Harry holds Quidditch tryouts. Ron narrowly wins Keeper position over a boy named Cormac McLaggen, who is angry he has not made the team.
During a trip into Hogsmeade, the friends witness Katie Bell become cursed from handling a Dark necklace from Borgin and Burkes. Her friend says she was going to deliver it to someone at Hogwarts.
At Harry's next lesson with Dumbledore, they look at a memory of young Tom Riddle. Tom has strong powers and uses them to hurt others. Even as a child, Tom had already begun to become Voldemort.
(The entire section is 1194 words.)