Tom Riddle's Diary

Harry and Ron discover a soggy, blank diary in Moaning Myrtle's bathroom, which had been thrown at her. The diary is fifty years old and bears the name T. M. Riddle. Harry takes it and, after experimenting, discovers he can communicate with the diary's owner, Tom Riddle, through written messages. Riddle reveals that he was the one who caught the person who opened the Chamber of Secrets fifty years ago, and he offers to show Harry the memory of that event. Harry agrees, and the diary pulls him into a vivid memory of the past, where he witnesses Riddle accusing Hagrid of being the Heir of Slytherin and setting a monster loose. The memory seems to confirm Hagrid's guilt, shaking Harry's faith in his friend.