Go to sleep

When you wake up, it takes a long while to remember where you are. It's become dark, night-time. What's this small bed? Oh, the cell! Hope they didn't leave for the night.

Fumbling around in the dark, you find that someone's been in the cell. They've left a small pile of clothes, a frilly costume, and a note.

Holding the note up to where the light is slightly brighter, you read:

"Party upstairs. Come join us when you wake up."

They've left the cage door slightly open for you