Night, and the people who prefer the dark come out of hiding. Musicians wake up, stretch, shower, and prepare to go to a gig. Clubbers put on their glitziest clothes and head to the city.
Late night workers arrive at their jobs. Cleaners come into buildings deserted hours ago and get rid of trash, scrub away the filth of the day. They dust shelves, swipe at desks ... maybe they read the note that one worker left by mistake in the corner of her desk.
Others emerge as well, from hidden corners and secret attics. They climb onto gutters and pipes, steady themselves for a moment, and launch their dark bodies from rooftops.
Perhaps they fly to spy on the Others, the ones who live by day. The dark ones, the night-dwellers, cling to windowsills and peer in at the sleepers. They wonder what the Day People dream about.
Maybe they have a regret or two, or else they accept it as the way things are. The night dwellers watch a bit longer until the Day People stir and turn over.
At that, the Dark Ones rise, and fly away again, until dawn's streaky bacon chases them back to their hiding holes, their prisons.