In the last battle, Harry Potter was shot by Avada Kedavra. Although he was lucky not to die, he also accidentally destroyed the soul piece on Harry's forehead, and finally successfully defeated Voldemort. However, because of the death curse, Harry's spirit was weakened. After the war, although the wizarding world restored peace. But the Potions Professor's words "look... At... Me" before his death became Harry's nightmare. Later, he wanted to commit suicide, but was stopped every time, which made Harry very painful. Harry's friends let him recuperate in the hospital wing of Hogwarts. However, Harry, who was mentally weak and jealous, inadvertently touched the secret room of Hogwarts and inherited the legacy left by the four founders. One of the magic items gave Harry another glimmer of hope, a hope that could save everything...
Going back to the past, it was Harry who saved the professor, or the professor who saved Harry.
PS: The introduction is incompetent, so let's just make do with it.