Harry Potter and the Half Blood Prince

In Harry's sixth year at Hogwarts, the wizarding world is in turmoil as Voldemort's power grows. Harry discovers an old Potions textbook filled with helpful notes and spells, marked as the property of the "Half-Blood Prince." This book helps him excel in Potions class and earns him the respect of the new Potions professor, Horace Slughorn.
Meanwhile, Dumbledore begins giving Harry private lessons to prepare him for the final battle against Voldemort. They explore Voldemort's past and learn about his Horcruxes, objects containing pieces of his soul that must be destroyed to defeat him. Harry also becomes suspicious of Draco Malfoy, believing he has become a Death Eater.
The story takes a dark turn when Dumbledore and Harry retrieve a Horcrux, only to find it is a fake. Upon returning to Hogwarts, they are ambushed by Death Eaters. In a shocking twist, Snape kills Dumbledore, revealing himself as the Half-Blood Prince. The book ends with Harry determined to find and destroy the remaining Horcruxes, setting the stage for the final battle against Voldemort