Harry Potter (Daniel Radcliffe) has finished his vacation and is about to return to Hogwarts to continue learning magic. A house-elf named Dobby warned Harry not to return to Hogwarts, otherwise he would be in great danger. Harry did not listen to Dobby's advice and returned to Hogwarts. Soon, a series of strange things happened in Hogwarts: students were petrified one after another, and the reason could not be found. And Harry could always hear a strange sound coming from the wall. Legend has it that there is a secret room in Hogwarts, which records the secrets of Voldemort's youth, and only Slytherin can open the secret room. Harry accidentally discovered that he could understand snakes talking, and it was rumored that Harry opened the secret room. Could it be that the danger that Dobby referred to is hidden in the secret room?