What is the book 《Harry Potter and the Half-Blood Prince》 talking about?摆脱大家简答,用英文,在50个词左右就行,更多最好!要写出梗概故事情节!好的话会追加分得!也不能太多啊！要保证我能在1到2 分钟内说完的！最好在40到75字，

Harry Potter and the Half-Blood Prince Harry enters a tumultuous puberty that,Rowling says,is based on her and her younger sister's own difficult teenage years.[12] Rowling also made an intimate statement about Harry's personal life:"Because of the demands of the adventure that Harry is following,he has had less sexual experience than boys of his age might have had".[13] This inexperience with romance was a factor in Harry's failed relationship with Cho.Now his thoughts concern Ginny,and a vital plot point in the last chapter includes Harry ends their budding romance to protect her from Voldemort.