Who Killed My Deskmate?

Chen Lu's deskmate died on the day after the college entrance examination. The cause of death is unknown. But strangely, four years later, Chen Lu actually received a text message from her. [Pick me up at the gas station. With doubts, Chen Lu came to the meeting place mentioned in the text message, but was unexpectedly reborn as a senior in high school. He planned to rescue his deskmate and analyze the possible causes of her future death. He would start by taking her for a physical examination and gradually find out the truth about her death. However, after his rebirth, Chen Lu encountered some strange things that were difficult to explain, and he gradually realized that this did not seem to be a simple rebirth. Will things really go as planned if he saves his deskmate?