The Ministry of Magic suffers defeat after defeat in battles with Voldemort. Even Muggles suffer from the second war - disasters occur every day, the causes of which no one knows. The Order of the Phoenix loses its best wizards in battles with the Death Eaters. But life goes on in war. Harry, Ron and Hermione, like all sixteen-year-olds, study, go to parties and fall in love. However, danger is getting closer and closer. Despite all the efforts of Dumbledore to protect the school, very strange events are happening at Hogwarts. This time the pensieve will reveal to Harry the biggest secret of the Dark Lord, and in order to win, Harry is forced to sacrifice the most dear... Which side in this war will the mysterious one take? Half-Blood Prince?