Celestia, it's your sister, Luna.

You know it's hard to justify
All this loneliness I hide
Behind my laughter
It screams in the night
Their terrified at the sight
But you always understood me, right?
Sometimes I'm confused when I wake
It's not like Equestria, dawn does not break
And I swear sometimes I see your face
And one million worries it does erase

Celestia, can I come back home?
Where everypony is free to roam
Celestia can I come and stay?
Let go of this nightmare way
Celestia, I made a huge mistake
All these tears I cannot seem to shake
Celestia, I am coming soon
I'm letting go of this Nightmare Moon

No, I'm way too big for that
I'll never wonder and that is that
I'll get used to this habitat
Say, "It's done, Luna, you'll never take it back"
But is it wrong your bedtime kiss I miss?
Signing off every day/night list
Why do I resist the urge to tell you this and
Celestia, I'm still here and I love you sis

Celestia, can I come back home?
Where everypony is free to roam
Celestia can I come and stay
Let go of this nightmare way
Celestia, I made a huge mistake
All my tears I cannot seem to shake
Celestia, I am coming soon
I'm letting go of this Nightmare Moon