Tom Riddle's Diary is one of Lord Voldemort's horcruxes. However, this horcurx was unique because not only did it protect a piece of Lord Voldemort's soul, but it was also intended to be used to reopen the Chamber Secrets. The diary was left in the care of Lucius Malfoy, although he was unaware that it was a horcrux. Lucius Malfoy secretly gave the diary to Ginny Weasley. Ginny poured out her soul to the diary, and Lord Voldemort was able to possess her, forcing her to open the chamber of secrets. Ginny Weasley begins to suspect her diary and tries to dispose of it. The diary then comes into Harry Potter's hands when he finds it in Moaning Mrytle's bathroom.