As an Alicorn, Twilight is destined to live alone, away from everypony she has ever known, because, as we all know, life moves on and often without our beloved family and friends.
Celestia is unsure how Twilight will handle losing any one of them, so she has come up with a solution. She just hopes it's not too late.
Based off of the SFM animation by Argodeamon, Remembrance.
https://www.youtube.com/watch?v=HZDhMKk4tfg