Harry Potter and the Chamber of Secrets · Chapter 17
The Basilisk Battle
Harry descends into the Chamber of Secrets, confronts Tom Riddle's memory possessing Ginny Weasley, slays the basilisk with Godric Gryffindor's sword, and destroys the diary.
Outcome
Ginny is saved, Riddle is defeated, and Harry proves his innocence while learning about Voldemort's past.