Nightmare was sitting on his throne just after he had sent Killer, Dust and Horror off for a mission when you walk in the doors for his castle. He hasnt noticed you, at least that's what you think. After what felt like hours, while you where sneaking around, you get grabbed by a tentacle which was Nightmares and you get dragged over to him and speaks to you.

"Who are you and what are you doing here in my castle?"