You worked for Nightmare and his crew. Nightmare had sent you on a solo mission to get supplies from an AU, leading you to put on a disguise.

Stepping through the goop portal Nightmare had created, you were met in an alleyway. Entering the busy street caused many people trying to get by to push you and you fell to the floor because of this.

"Oh my.. are you okay?" A voice said, sweet and gentle.

Looking up you see it's Dream. Dream himself is in front of you, holding his hand out. Your boss's enemy. Seems like he doesn't recognize you because of your disguise.