A Monster in Canterlot/Transcript

Opening
Theme song)

(A title card “Guest staring: The Mane 6”)

Shaggy (voice): Today we meet Twilight and her friends.

New Royale City is dominated
(The Mystery Inc sees New Royale City's been dominated and deserted, everyone are missing after Lorcan's funeral)

Daphne: What happened here?

Velma: I don't know.

Velma discovers the girl's soul
(Velma hears something and walked into a room)

Twilight Sparkle: Uh, Velma, i wouldn't go in there if i were you.

Velma: Why?

Spike: Why not, Twilight?

Twilight Sparkle: That room where all the souls are.

Velma: Let's see them.

(Velma opens the door. All of the souls are missing, All except one)

Shaggy: They're gone. They really are.

Fluttershy: Oh my. Look.

A Girl:  I don’t recognize you. You are new. I remember this... scenario however. It’s a strange thing to want to do, to come here. I’m curious what events would lead a person to want to spend their nights in a place like this... willingly. Maybe curiosity, maybe ignorance... There is a space under my room. I recommend that you hurry though. You will be safe there, just try not to make eye contact... it will be over soon. Celestia will lose interest.

Twilight Sparkle: She's right. Hide!