Harry Potter and the Chamber of Secrets

I read the book Harry Potter and the Chamber of Secret, it was as good as the first one, another incredible creation by J.K Rowling. The plot was very interesting, I could not take my hands of it until I have finished reading it.

Harry Potter and his friends is returning to Hogwarts School Witchcraft and Wizardry for their second year of magical education. Harry received a fishy warning from the house-elf named Dobby, warning him not to go back to school because there is a plot to kill Harry. Dobby blocked the magical barrier leading to the train to Hogwarts, instead, Harry and his best friend Ron arrived at Hogwarts in a magical flying car. Muggle-borns are being petrified around the school, soon, Harry discovered he could speak Parseltongue, many people believed he was the heir of Slytherine and he had opened the Chamber of Secrets, controlling the giant basilisk living in it to petrify and kill. Ron's younger sister was brought down to the Chamber of Secrets.

Who is actually behind all this horror? Will Harry and Ron survive the deadly battle against the giant basilisk?