Harry Questions the Identity of the Half-Blood Prince

After the Potions lesson, Harry, Ron, and Hermione continue discussing the scribbled notes in the book Harry used to win Felix Felicis. Hermione remains skeptical and casts a spell to check the book for anything unusual, but nothing happens. As Harry retrieves the book after it falls, he notices a note written inside the cover identifying the book as the property of the "Half-Blood Prince," leaving Harry intrigued about the identity of the mysterious former owner.