It has been over five months since Starswirl the Bearded had vanished from his laboratory in the Castle of the Two Sisters, and Princess Celestia has all but given up hope of ever finding him again.
That is why, when the wizard's famed pupil, Clover the Clever, comes in with new information regarding his disappearance, Celestia is overjoyed at the chance that she may get to see her oldest friend once more.
Only, instead of giving a location, Clover recounts the story of how she first met the legendary wizard, and how it was also the very last time that Starswirl ever saw her.