Hye-jeong (Han Hae-in), who works in a factory on the outskirts of the city, can't afford a relationship like everyone else. One day Hye-jeong wakes up as a ghost in her room, not knowing what happened. Time goes backwards for Hye-jeong's ghost, and at the Door of the Night she meets Hyo-yeon (Jeon So-nee). "A ghost who has no tomorrow walks back the way it came from so that it doesn't disappear. They make sure everyone is asleep before they stop walking."