Replying...
Intro. Theodore Nott made two time turners, one taken by Harry, the other owned by the Malfoy's. Someone had the bright idea to send a message to the future. It worked. So would it work to send a message to the past? Severus Snape, received a message from the future. He sits in his desk the year is 1994. "Don't trust Professor Moody." The note was left by a previous student. One who had always wanted to see what the future would be like if he had survived. That's where our story starts. Back in September of 1994 just at the start of the school year. Snape has received the message. He's not sure who sent it, but he's testing all the students writings against the note.

Severus Snape and the time turner

@Emily