Harry approaches a door with snakes on it and opens it using Parseltongue. Man that skill is coming in handy. Then he crawls down into a huge room. Hey, it's the Chamber of Secrets we've been hearing so much about.
At the end of the chamber is Ginny's body. Harry runs towards her hoping she's not dead.
Just then, a young man steps out of the shadows. It's Tom Riddle. Funny seeing him here. He tells Harry that Ginny is alive.
Harry wants Tom's help to save Ginny, but Tom is acting a little fishy. He picks up Harry's wand and won't give it back. Then he tells Harry that he's feeding off Ginny's weakness to grow stronger.
Oh, yeah, Tom explains. See, it was Ginny who opened the Chamber of Secrets and sicced the basilisk on everyone and wrote those messages in blood. Sure, she only did it because Tom told her to and she was in a trance, but still.
That's why Ginny tried to ditch the diary in the girls' bathroom.
Tom was actually pretty psyched when Harry found it. He had really been looking forward to meeting Harry so he showed Harry his memory of the time he framed Hagrid for opening the Chamber of Secrets.
Harry is pretty annoyed by this. Tom is a huge liar.
Yeah, whatever, Tom tells Harry. Only Dumbledore thought that Hagrid didn't do it. But Tom knew he couldn't risk opening the chamber again at school so he left behind the diary with a memory of his sixteen-year-old self preserved inside. He knew that one day he would get someone else to finish the work that Salazar Slytherin had started.
Well, Harry tells him, your plan is an epic fail. You didn't kill anyone, you just petrified them.
Seriously? Tom replies. I don't even care about killing Mudbloods anymore. I'm more worried about killing you, Harry.
And then Tom goes in for the big reveal. He writes his name in the air with Harry's wand—Tom Marvolo Riddle—and then he rearranges the letters to spell the phrase "I Am Lord Voldemort." Holy anagram, Batman.
Tom Riddle is the heir of Slytherin. He is Voldemort. 1 + 1 = 2. It all makes sense now.
Tom is pretty pleased with himself. He's just a memory and he's achieving all his goals. He's even driven out Dumbledore.
Nope, says Harry. Dumbledore will always be here if people are loyal to him. Bold words.
Just then Fawkes flies into the chamber and tosses the Sorting Hat to Harry.
Gee, Tom tells him. Dumbledore is pretty awesome. He gave you a hat to fight me with. I'm so scared. #sarcasm