This is tagged as a romance. It won't be overly, um, gross. Evil guy gets a crush, and he tries to kill/enslave her friends and family. She hates him, he loves her. Great relationship.

Anyway, Celestia's uncle returns. Luna rejoices, for she has no memory of him. Celestia remembers, and is dismayed by his return. She wonders if she can ever forget her race's past as she experiences nightmares, which her uncle turns into a reality.

Will the pony he has a crush on be enough to show him the errors of his ways? Probably not, concidering she is a "lower form of life" (not Alicorn). But that doesn't stop Lord Nebulae from getting feelings for her.

You've probably guessed who it is, haven't you?

This is shortly before Twilight becomes an alicorn.