A princess gets kidnapped by a demon king and immediately starts demolishing his castle from the inside to build a better pillow fort. The joke never wears out because the show doesn't bother with plot, it just watches her systematically destroy everything around her for comfort, one absurd nighttime scheme at a time. Every demon in that castle exists only to enable her chaos, and they're all too tired to stop her.

Princess Syalis has been kidnapped by the Demon Lord Tasogare and locked away in his monster-filled castle, while a hero sets out back home to rescue her. Syalis is not frightened by her captors. She cares about one thing only: she has not had a decent night's sleep since she was taken, and her cell is dull and uncomfortable. So she sets out to fix that with whatever the castle offers, turning the fur of winged demonic teddy bears and the soft, sheet-like bodies of ghost shrouds into bedding and other sleep aids. Nothing will keep her from a good rest, not even death. A lighthearted fantasy comedy with a slice-of-life feel, built on a captive princess who treats a sinister prison as a place to find a comfortable nap.