Harry Potter and the Chamber of Secrets

Harry Potter spends his summer with the Dursleys, where a house-elf named Dobby warns Harry of impending danger at Hogwarts. He attempts to prevent him from returning by sabotaging an important dinner. After being blocked from entering Platform Nine and Three-Quarters, Harry and Ron fly their father's flying car to Hogwarts, where they crash into the Whomping Willow. There, they hear a message written in blood: "The Chamber Of Secrets has been opened."