Years after her coronation, Twilight finds an abandoned "Tardis" in her room. When it turns out to be a time machine, the princess decides she wants to relive her adventures with her friends, but she accidentally changes the future of all the ponies in Equestria! Now, with the help of Queen Chrysalis and the Cloud Sisters, Twilight Sparkle must return everything back to normal if she ever wants to get the Tardis back. But what if she can never confront the Sun Princess after the horrible prank Rainbow Dash blamed her on?